So, we have found what was the problem. It was coming from a php.ini in the wp-admin folder. We deleted it after making some backup to see if it will solve the problem and now everything works just fine.
Thank you for your help santeven.
I have the latest version of wordpress and I tried with no plugin and the default theme. Nothing worked.
Hi santeven,
There’s only the admin account on the website for now. I just check to make sure and I still have admin access. So I don’t think it’s coming from there.