Unable to login

Last night I tried to post to my site and it looked like it was posting, but didn’t actually create the post. After a few times I decided to sign out and back but, but haven’t been able to sign in again since. When I try to sign in, it just goes back to the login page. If I try a different username it recognizes that it doesn’t exist. I’ve tried multiple browsers and devices with the same results. I’ve tried renaming the Plugins and Themes folders, resetting my password both through the link and through mySQL. I’ve tried deleting .htaccess and a few code edits I found in the forums. Everything I’ve been able to find about this so far was from 5 or 6 years ago, so obviously a different version of WordPress.

I can sign in through the Android app and see my previous posts, but if I try to upload a new post I get an error. Previously the error code was 480, but when I tried again just now to get the exact wording of the error it gave a new one. The new error is “An error occurred while uploading the Post Could not insert post into the database [Code: 500]”.

If anyone else has had this issue recently and has been able to fix it or knows of anything else I should try, I’d really appreciate it.