"Add Media" and "Set featured image" buttons don't work

[ldh27513]

when I upgrade to 5.5 I lose editing functions, the "AddMedia" button stops working along with set featured image. after upgrade neither works
Before the upgrade this wasn't an issue, and I could add images through these options.
Also the text updating seems to be unimpaired
I use Select Classic Editor,Classic Editor Addon.
This so debilitates the issue I had to roll back to 5.4.
It'd sure be nice to get a debugged version of 5.5 out _soon

[johnbillion]

Welcome @ldh27513 and thanks for the report.

These issues may depend on a change in WordPress 5.5 related to the jQuery library. Are you seeing any JavaScript errors in your browser console?

If so you might need to check the information on this support topic under the section "jQuery Migrate is disabled by default": ​https://wordpress.org/support/topic/read-this-first-wordpress-5-5-master-list/#post-13238244

If that is the case, it means one or more of your plugins or the active theme are using JavaScript code that is incompatible with the jQuery change in WordPress. Ideally, these plugins (or the theme) should update their code. If no update is available at this time, there is a "jQuery Migrate Helper" plugin available on the support topic, please see the instructions there. If that solves the issues you're experiencing, please report back. That would be much appreciated so that issues triggered by this change can be better tracked :)

More technical info about the jQuery change:
​https://make.wordpress.org/core/2020/06/29/updating-jquery-version-shipped-with-wordpress/

If that turns out not to be the case, feel free to reopen this ticket with more details after you've checked that all your plugins and themes have been updated to the latest versions.