Random 404 errors throughout WordPress

I’ve reinstalled all plugins, changed themes and cleaned up my Database. So far i get random 404 errors but it’s all on the back-end from what I can tell. I’ll save a post, go to a setting page, update settings or upload a media file. When I get the 404 sometimes I lose information I just entered (like if I’m posting). Sometimes it won’t.

Frustrating at times when I’m working on pushing a post out. Need some advice here. Thanks!