ConvertPlus Not Saving — Return of the JS Error

Hi folks,

Having issues with ConvertPlus not being able to save, similar to the error described in Dec '20.

I’m getting 4 errors, repeated:

Uncaught TypeError: this._addClass is not a function (autocomplete.min.js?ver=1.12.1:9)

jquery.min.js?ver=3.5.1:2 Uncaught TypeError: this._addClass is not a function

slider.min.js?ver=1.12.1:9 Uncaught TypeError: Cannot read property 'stop' of undefined

Uncaught TypeError: is not a function at receiveMessage (customizer.js?ver=3.5.17:37)

The last error is the only one that appears to be coming from the CP plugin. I’ve cleared my cache, server cache, updated all plugins, etc. Could there be some jQuery version + CP+ WP conflict?

Hi @lukefinsaas,

The error mentioned in the given thread was already resolved by the plugin development team and updated with the latest version of the theme. If you didn’t update it yet, I would request you to update it and in case you are using the X please update it by following the below steps

  1. Delete the existing Cornerstone plugin
  2. Update the X theme to the latest version on automatic updates
  3. After the X theme is updated, use the link in the dashboard to automatically install the Cornerstone. It will be at the latest version

If all are updated and you are still getting the issue, there might be some different reason behind your reason, I would like to suggest troubleshoot the following common issue to help us to recognize the reason.

1.Plugin Conflict
2.Theme Update related issue
3.Child Theme Related issue ** if activated
4.CSS/JS Customization
5.Disabling Cache
6.Disabling CDN

If you discover that an issue is coming from a custom code or 3rd party plugin, kindly consult with a developer or contact the plugin author. Please note that we do not provide support for custom codes and 3rd party plugins.
If none of the above helps, please provide login credentials for your site in a secure note to investigate it further, including:

– WordPress Site URL & Login URL
– WordPress Admin username/password

To create a secure note, click the key icon underneath any of your posts.


Hi @tristup,

I’ve already updated X and Cornerstone to the latest. I also deleted and reinstalled ConvertPlus to get it on the latest version. I understand that updates were made to the plugin/theme and the other user’s errors were resolved, but unfortunately, the updates haven’t resolved the issues for our site (hence, the Return of the JS Error).

Is there a way to delete Cornerstone and reinstall it, without an update to X? I feel like I did it years ago, but X is quite different now :slight_smile:

If not, I’ve gone through the six step list already. Understand that you can’t support 3rd party plugins, but X license holders don’t hold personal licenses with ConvertPlus so makes it a bit difficult to get support in that direction.

Appreciate the assistance. Thanks!


Hello Luke,

Kindly provide us access to your site so that we can check your settings. Please create a secure note with the following info:
– Link to your site
– WP login URL
– WP username
– WP password
– WP Administrator Role
- Confirmation that we can access and make changes to your site

To know how to create a secure note, please check this out: How The Forum Works


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