Are you able to connect to pop server .Try this command
Start>>run>>cmd>> telnet mail.your domain name 110
If you are unable to connect then it must be problem with yor hosting provider mail server .
If you are able to connect , then
Clear the cache and disable the firewall on your local machine that might be blocking the port 110
Also check the disk space and quota for the domain and email id from cpanel>>mails
Do you face problem in sending mail ?
check the basic email setting
Most email applications only need the following information:
POP3/Incoming Mail Server = mail.yourdomain.com (replace yourdomain.com with your domain).
SMTP/Outgoing Mail Server = Use the setting for the outgoing mail server provided by your ISP or mail.yourdomain.com (replace yourdomain.com with your domain).
Account Name = Whole email address is your account name ( not what just appears before the ' @ ' symbol )
Password = password that you entered while adding the pop3 account from the control panel interface
POP3/Incoming port : 110
SMTP/Outgoing port : 25
Enable "My server requires authentication" option.
