I'm aware there are already some threads regarding this error message here, but I did not manage to solve this. In the JS console it says: POST ../admin/EditForm 404. But where do I go from there? On the server error logs I did not find anything.
I know that it has to do with HTMLText that won't get saved to the database, if I remove the field that holds that data, everything saves fine.
I have just upgraded to 2.4.6 by the way, but I think these errors happened before.
Has anybody encountered this specific problem? I'd be grateful for any help.
P.S. I copied the entire site to my PC and there it all works. Any clue what kind of server settings could be responsible?