some DNS problem

I have a problem with my POP3 download connector.I can't receive E-mails from my free POP3 server. When connect everything is OK , but when POP3 connector close connection then is trying again. And in Event viewer is error text.

No DNS server found. Domain name resolution will fail
thus mail will not be properly delivered. Since there are
no DNS server around, we will default to regular
WinSock calls.

Check the Phone Book Entry for the dialup connection and enter the Primary and Secondary name servers there. Also, check DNS settings in Control Panel, Network.

Or instead of entering the mail server name as "mail.server.com" for example, use the IP address (ping the host when online). However, if the ISP were to change it, you would not be able to connect.