Firewall Block – Make sure that your local system’s IP address is not blocked in firewall of server. You will need to check the firewall logs for it.
1. Failed cPanel login attempts –
If you’ve entered the wrong password while login to cPanel from your local system then your IP will get blocked.(there will be limit set on your server for failed login attempt on your server)
2. Failed IMAP/POP/SMTP/webmail login attempts –
IMAP/POP/SMTP Login –
If you’ve configured the email account using IMAP/POP/SMTP in any of the email client and tried login to email account in email client using wrong password (there will be limit set on your server for failed login attempt on your server) then your IP address will get block.
Webmail Login –
If you’re trying to login to your email account using webmail client with the wrong password then there will be limit set on your server for failed login attempt on your server) then your IP address will get block.
3. Failed FTP and SSH login attempts –
4. Port Scan attack –
If there are multiple requests for connection to server from your local system’s IP address then there will be might be possibility of port scan attack. That means the attacker is trying to find the open port on server for vulnerable activities.
So on every server there is connection limit from one IP address.
Let me know your thoughts on it. 🙂