I have the same problem, “the response is not a valid JSON response” I have tried to do a lot of things, from using backups, reinstalling wordpress, changing the PHP version, activating the classic editor, deactivating Gutenberg, updating the plugins, deactivating the plugins one by one to see if the error appears and nothing.
I have the idea that this problem may have to do with the SSL certificate, I will try to request them again to see if this will work.
I’m also using Namecheaps as hosting and I don’t know if the problem was caused by them, they recently switched to Litespeed technology and surely the problem is in the migration to a new server.
If I get to solve the problem “the response is not a valid JSON response” I will let you know.
If anyone can help, we would appreciate it.
