Are you getting this error in Proxmox while trying to apt update or install Ceph?
apt update
Hit:1 http://security.debian.org bullseye-security InRelease
Err:2 https://enterprise.proxmox.com/debian/pve bullseye InRelease
401 Unauthorized [IP: 144.217.225.162 443]
Hit:3 http://ftp.hk.debian.org/debian bullseye InRelease ........
Just a note before you do this you should have a sure, guaranteed way into the system such as local, KVMor preferably publickey making bruteforce SSH absolutely impossible since there is no password to bruteforce and even if someone knew the password they wouldn't be able to login except from the local console (presumably you should make sure no one unauthorized has physical access).
1. Edit /etc/ssh/sshd_config
Find the section like this:........