Craft entries won't save (new or edits) So I am trying to create a new entry, but every time I click save, nothing is actually saved. (see gif) 



THINGS I HAVE TRIED:


Overwriting the app folder with a freshly downloaded one (I am already on the latest stable build)
Increasing max_input_vars and post_max_size in my php config


THINGS I HAVE NOTICED 


It works if I leave the rich text field blank, or with minimal content (like maybe 2 sentences) 
Nothing ever makes it to the database, _entryversions remains unchanged
I don't see anything weird in my log, e.g. no [error] tags


Craft Version: 2.6.2990

Thanks in advance for your help!
For anyone experiencing this issue, what solved it for me was deleting the craft application files and replacing them with the ones from the same release version.

It seems one of them got corrupted at some point.