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Common errors and how to fix them
Common errors and how to fix them

We have all seen many error messages while developing our applications. Especially for beginners these messages can be challenging.

Marton Szilard avatar
Written by Marton Szilard
Updated over a week ago

Runtime errors

1. An interface may only extend a class or another interface

This error occurs when the Angular/Ionic application's typescript version is older than the minimum required by the Mobiscroll. Mobiscroll will need at least typescript 2.2.0 or newer.

Solution: Update typescript version: npm install typescript@latest --save-dev 

2. Angular template parse errors

  • Can't bind to 'mbsc-options'  since it isn't a known property of 'input' 

  • 'mbsc-calendar' is not a known element

  • There is no directive with "exportAs" set to mobiscroll

The above errors are usually occurring when the MbscModule is not exported by the *.module.ts file. Most likely the MbscModule import is missing or is not correct  in the module file.

Solution: Make sure that the Mobiscroll is installed and the MbscModule is loaded correctly in the module.

Note:  If you are using lazy loading, the MbscModule has to be imported into every module separately.

3. Mobiscroll is not loaded or it is not loaded correctly

Error message:

mobiscroll is not a function

The above error is occurring when the Mobiscroll is not loaded or it is loaded in the wrong place. When the JS code runs it tries to call a mobiscroll function, but it's not finding it.

Solution: Make sure Mobiscroll is loaded correctly where you want to use it. Also, our getting started guides can be really helpful in solving this issue.

Note: This error message occurs when you try to use Mobiscroll together with jQuery or Javascript.

Contact us if something is unclear or just need a little bit more help with solving this problem.

4. Mobiscroll trial not loaded: Please check your connection

This error appears in an alert when the the Mobiscroll trial doesn't have access to the internet. It usually occurs when the application is deployed to a device which is not connected. The trial needs an active internet connection to work.

Solution: Make sure to have an active internet connection during trial and your project's configuration doesn't block the Mobiscroll external API call.

Make sure that the url is white-listed in the CSP settings and in case of Cordova/Phonegap applications added to the cordova-plugin-whitelist plugin's  settings.

Note:  This is not a requirement of the licensed version. You can use the non-trial products offline.

Learn more about the limitations of the trial in this article.

5. A Specific Mobiscroll component is not working

Here are the error messages with a range component example:

  • Plain Javascript: mobiscroll.range is not a function

  • jQuery:  $(...).mobiscroll(...).range is not a function

  • Angular 2+/ Ionic 2+ : mbsc-range' is not a known element

  • AngularJs/Ionic 1: [$injector:modulerr] 

The above errors are occurring when the component was downloaded from the Download builder and the specific component wasn't included into the downloaded package.

Solution: Download resources again and update your local package. Make sure to check all the components you need in the 1. Choose Components section. Updating the local Mobiscroll package should solve the problem.

6. Components don’t look like expected. Styling is not applied

Here is how a Calendar and Date component looks like without styles:

A few things to check to solve this problem:

  • Check if you passed the correct theme name to the theme option

If there is a typo in the theme name that could cause this problem.  If you are using a custom theme, make sure that you pass the generated UniqueID name to the components. The UniqueID will be auto-generated after you named your custom theme on the Theme builder.

  • If the theme name is correct then check if the Mobiscroll css/scss is correctly loaded to your app.

This might be a project related manner, but here are some tips you might check. In case of:

    - Ionic 4/ Angular cli based app  make sure that the css is loaded into the angular.json file's styles  section. Or if you use scss then check if  there is a mobiscroll scss import in the global.scss. In case of an Angular app you should check the styles.scss  file for scss import.

    - Ionic 3 make sure that the css is included into the index.html  and an Ionic_copy  section is specified in the package.json  file which describes where to copy the css form the node_modules. Or if you use scss then check if  there is a mobiscroll import in the variable.scss file.

    - JavaScript, jQuery, AngularJs  make sure that the css is loaded in the index.html  and there isn't any css related console errors.

  • Check if the specific theme is loaded into your Mobiscroll package

This section is only valid for the licensed users because only they can use the Download Builder to specify which Mobiscroll resource would they want to use. (The trial users have all the resources included in their packages)
There might be a chance that you missed including the specific theme when you created your Mobiscroll package. 

Solution: Download resources again and update your local package. Make sure to check all the themes you need in the 2. Choose Themes section. Updating the local Mobiscroll package should solve the problem.

There are differences on the package update process in case of React, Angular 2+ / Ionic 2+ frameworks. You'll need to use the Mobiscroll CLI's config  command  with the --no-npm  flag. You should be prompted with a detailed step by step install/update guide on the download page after you downloaded your new package.

In case of other frameworks just simply updating the local Mobiscroll files should solve the problem.

7. No provider for Jsonp

If you are facing with this error message, here's the solution: 

ERROR Error: Uncaught (in promise): Error: StaticInjectorError(AppModule)[AboutPage -> Jsonp]: 
StaticInjectorError(Platform: core)[AboutPage -> Jsonp]:
NullInjectorError: No provider for Jsonp!

It's because some of our demos use remote API for loading external data. In this case make sure to load the Jsonp module in your app's module file.


import { JsonpModule } from '@angular/http';
// ...
 imports: [
   // ...
   // ...
 // ...
// ...

Note: This issue could come up when you use Angular or Ionic.

8. Content Security Policy errors

  • Refused to load the font

    This may happen if the icons were downloaded with the "Embed in CSS" option, so the font icon is embedded in base64 encoding in the css file. Make sure to add  font-src 'self' data: to your CSP directives. Example:

    <meta http-equiv="Content-Security-Policy" content="default-src * 'unsafe-inline'; font-src 'self' data:" />

9. Events are not loaded/shown in the Event Calendar

If you are trying to get/load data/events from an external link to the Event Calendar and the result is that the events are not shown in the calendar:

The problem might be that you are returning a simple JSON, while the demo URL return the values in JSONP format which is a little different.

The JSONP is used for sending JSON data without worrying about cross-domain issues and internally it uses the <script> tag instead of the XMLHttpRequest object.

Also, the JSONP request requires a different response from the server that's why it was not working for you when you returned a normal JSON data


If you don't need to handle cross-domain requests you are good with serving plain JSON. If this is the case, in our example you just need to change the second parameter of the getJson function.

The actual demo on our webpage uses JSONP, so the code looks like this:

mobiscroll.util.getJson('yourURL', function (events) {

// ...

}, 'jsonp');

BUT you will need:

mobiscroll.util.getJson('yourURL', function (events) {

// ...

}, 'json'); // change this parameter from 'jsonp' if you want to use simple JSON data


Some of our demos use remote API for loading external data. For example, in case of Mobiscroll Event Calendar (in most cases) the events are loaded from an external link with the help of getJson function.

10. Date format problem in case of iOS Safari

If you are using Mobiscroll components and you notice that certain things don't appear on iOS however the same things work/ show up in Chrome and Android: such as events, `marked` or `invalid` options that are associated with a given date - this is most likely the problem.

Based on conversations with our customers in many cases they try to create javascript Date objects from non-standard formats, for example: `new Date('10/29/2020')`.

So, the problem is that some non-standard formats will work in some browsers (e.g. Chrome), but in others (e.g. Safari) the result will be an invalid date.


  1. Mobiscroll supports ISO8601 date strings, so if you store your dates in that format, you can pass the date strings directly, without converting to date: '2020-10-27'.

  2. If you can't (e.g. you can't change in your database where they are stored this way), you need to parse the date appropriately:

Installation errors

Note (June 1, 2023):

We had an issues with our private npm registry on May 31, 2023 that has been fixed. New tokens will be needed since the private npm registry had to be rebuilt internally.

First thing’s first, the CLI: Make sure to have the Mobiscroll CLI installed. More info on it here - (make sure that you have at least Node.js 11 installed).

In case of NPM and Yarn 1: Call a mobiscroll login in your application root folder (use the email address and password of the licensed account) followed by pushing the .npmrc into your repository for CI/CD.

In case of Yarn 2+: Call mobiscroll logout followed by a mobiscroll config {framework} to install the latest version or specify the exact version like mobiscroll config {framework} --version 5.22.3. This will take care of refreshing the tokens after which you can push the .yarnrc.yml into your repository for CI/CD.

Caching and checksum issues: Since the npm packages were rebuilt, the checksum of the packages changed and in some CI/CD environments this causes problems.

If that’s the case try deleting the package-lock.json (in case of NPM) or yarn.lock (in case of Yarn) files, and run npm install / yarn install again, and push the updated files to the repository.

In some cases, when using Yarn, running yarn cache clean --all is also necessary (locally and on the server).

If cleaning the cache does not work, try setting the YARN_CHECKSUM_BEHAVIOR=update env variable on the CI/CD environment.

1. npm ERR! 403 Forbidden

This error usually occurs when the Mobiscroll npm package couldn't authenticate. There can be multiple causes:

  •  The user doesn't have access to the npm package

    The npm packages contains the full set of Mobiscroll controls. This error usually occurs when the user has a component license and tries to install using NPM.

    Solution:  Download the package manually.

  • The package is used on a CI or AWS server, and the authentification token is missing

    Solution: an .npmrc  file with the Mobiscroll auth tokens should be present in the project's root directory. The mobiscroll config  cli command should generate this .npmrc file by default.
    If you don't have the .npmrc file in your project's root directory, check the following folder for  a global .npmrc: $HOME/   on Mac and Linux and Users/{Username}/  on Windows. If the file exists, delete the Mobiscroll related auth tokens from it. After this you can re-run the mobiscroll config command in your project and push the newly generated file to your repo.
    Make sure the .npmrc file is under source control (is not ignored), and is present on the CI/CD environment.

  • If the Mobiscroll account's password was changed

    If you changed your account's password then previously generated Mobiscroll npm auth token won't be valid anymore.

    Solution: Delete the Mobiscroll related content form the .npmrc file, and run the mobiscroll config  command once again.

2. npm login failed. URL is not defined

This error message usually occurs when you're using an older Node.js version. The CLI requires at least Node.js 11.

Solution: Please try to upgrade at least to Node.js 11.

3. npm login failed. Not Found

This error message usually occurs when your email address contains a specific character for example '+' . The NPM registry has some issue with this character.

Solution: You can use the account's username for the login and you can also change if you want from the accounts page

4. User {username} has no access to package @mobscoll/{framework}

The npm packages contains the full set of Mobiscroll controls. This error usually occurs when the user has a component license and tries to install it using NPM. The error also occurs if the user doesn't have a license assigned. 

Solution: Download the package manually.

5. Could not find user with the specified username or password

This error is thrown by the Mobiscroll NPM registry and as the error message indicates this might be either because you mistyped your login information or  your account does not exist.


6. Proxy related issues

If you're behind a proxy, the installation process might not be able to send the necessary requests. The following errors indicate that there's a problem with the proxy configuration:

  • Error: getaddrinfo ENOTFOUND

  • Error: getaddrinfo EAI_AGAIN

  • Error: connect ETIMEDOUT

  • Error: tunneling socket could not be estabilished

  • Error: socket hang up


  • Set the http_proxy and the https_proxy environment variables.

  • If you do not want to add or modify the system environment variables, use the --proxy option to pass the proxy server address to the config command (replace your_user, your_password, your_proxy and the port 1234 with your actual proxy configuration)

    $ mobiscroll config [framework] --proxy

7. Certificate related issues

In certain environments, behind a strict firewall, the config may fail with one of the following errors:

  • Error: unable to get local issuer certificate

  • Error: self signed certificate in certificate chain


  • Bypass the ssl verification by setting the NODE_TLS_REJECT_UNAUTHORIZED environment variable to 0. This should be used only as temporary solution, since this will bypass ssl verification for every request from Node.js, which is not secure.





  • A permanent solution would be to set the certificate file using the NODE_EXTRA_CA_CERTS environment variable. Ask your system administrator for the location of the certificate file.


    $ export NODE_EXTRA_CA_CERTS=/path/to/your/cert.pem


    $ setx NODE_EXTRA_CA_CERTS /path/to/your/cert.pem

For more details on the topic please read this article.

8. Permission issues

When running the config command, you might run into errors indicating the the config command is unable to write in the project directory:

  • Error: EPERM: operation not permitted

Make sure that the project folder is writable by the user running the mobiscroll config command.

9. Execution policy issues

On Windows client computers, the execution of PowerShell scripts is disabled by default. When installing the Mobiscroll CLI on Windows using a PowerShell you might run into the following error:

  • npm : File C:\Users\...\npm\npm.ps1 cannot be loaded because running scripts is disabled on this system.

Solution: to allow the execution of PowerShell scripts, which is needed for npm global binaries, you must set the following execution policy:

Set-ExecutionPolicy -Scope CurrentUser -ExecutionPolicy RemoteSigned

Carefully read the message displayed after executing the command and follow the instructions. Make sure you understand the implications of setting an execution policy.

Other problems

1. Cannot access variables and methods form Mobiscroll events with this keyword

A function's this  keyword behaves a little differently in JavaScript compared to other languages. The problem usually occurs with those frameworks where the this keyword is used to access the app's methods and properties. 

If the mobiscroll events are defined the following way: 

onBeforeShow: function (event, inst) {
     // this.yourPropertyName won't point to the actual property

In Mobiscroll event handlers that are defined like above, this keyword points to the element where the component was initialized.

Solution: The easiest way to solve this problem is to use ES6 arrow functions where this retains the value of the enclosing lexical context's this:

onBeforeShow: (event, inst) => {
     // this.yourPropertyName will point to your actual property

If you couldn't solve the error which you are experiencing get in touch at

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