I’m looking at the server logs folder and have no idea what to look for inside.
access.log.2021-09-10.gz t0 13 are timestamped from2021
error.log.2021-09-10.gz to 13 are also from 2021
You are looking for the “error.log” file (not the other two). You need to find the current file – i.e. the one with the entry for the date / time the error occurred. The one you mentioned here seem to be from last year. If you have those then somewhere should be the current ones. Perhaps your web host can tell you where they are?
Once you have the right file, and the approximate date / time in that file, there will be a message in there that describes an error that has some mention if “user”, or admin_users.php” or similar in it.