404 Eror

@doremi123, try to switch to standard theme and check if issue repeats.

Also try to disable other plugins and check that issue repeats.

Currently this issue not repeats on standard wordpress install.

Switched to a standard theme, disabled all other plugins – the problem repeats. Error 404 page not found – when saving the results of the configuration

@doremi123, does it looks same when you try to open non-existent page on your site?

Just show us how it looks like, which URLs do you haev inside test and on 4040 error?

Contact your hoster to research web-server’s and php’s erorr logs.

For any actions, when I want to save, I’ll get an error
Screenshots:
1) https://drive.google.com/open?id=0B64UHVq7JwqQZkdRTTkyVWVfenc
2) https://drive.google.com/open?id=0B64UHVq7JwqQQVhkZVJTUGtvQ1E

Google for “wordpress post save 404” and try different workarounds.

Currently I see it’s your hoster/host/wp install issue.