I have several servers running KeyHelp, but I'm having problems with one of them. When I try to access it or any of the websites it hosts, either via SSH or FTP, it doesn't respond. However, if I activate a VPN or access it from a different IP address, it works perfectly. Does KeyHelp have some kind of firewall that restricts access by IP address? It's running on Debian 12.
Regards
Keyhelp has a firewall (iptables). It also uses fail2ban, which might be responsible for your problem. This will ban IPs that fail authentification several times (ssh, smtp, imap, pop3,...). Take a look in the Keyhelp admin panel "Security->Fail2Ban-Management" to see if your IP is listed. You can also unban it from there. Also check for correct user and password settings of mail accounts in all your mail clients. It's also a good idea to whitelist your own IP (if it is a static IP) in fail2ban config (ignoreip).