URGENT suddenly unable to save any post or pages

Valued Support-Team,

please be so kind help us out. By sudden we are unable to save post’s or pages on our subdomain project.bestof… We can’t figure out what might cause the problem being suddenly unable to save new or updated page/post and trust, you professionals can help us out.

The page we last had on update is 09 – Launch & Execution which permanently request

The backup of this post in your browser is different from the version below. Restore the backup

BUT even this is not possible anymore.

Thought, Permalink could have a hickup; we changed it structure temporarily to something else and back again. But issue still exist. We checked out other features on that domain, they work all properly.

Please request direct server access.

Thank you in advance.