I just migrated from development to production site and reentered the new key. I am still getting the error when setup Toolset site keys.
Solution:
Please check these:
1) Make sure you are using the latest version of Toolset plugins(especially the Toolset Types plugin), you can download them here: https://toolset.com/account/downloads/
2) Follow our document to setup the Toolset site key, and test again:
Style container block with custom CSS class names.
Solution:
You can edit the page/post, find and select the "Container block", in the sidebar, section "ID & Classes", setup your custom CSS class names, see my screenshot:
Solution:
You should try to click on Recover Block and see if that helps. If that does not help, you should try to remove the existing block and try to build it from scratch.