Can Send Email, but cannot receive, Except out of Office!

[djpanic]

Send works fine. Webmail works fine, old Email account under same domain works fine, even on this PC, just not new or existing account on this PC or any PC. Checked settings, software, tried alternative configs (different Pop servers, the IP instead of the name, etc). Uninstalled and reinstalled Outlook, deleted and recreated the Pop account both in Outlook and on the hosting company, still nothing. Checked settings a hundred times of course. The environment is a Windows 2003 Small business Server, the clients are all Win XP Pro. DNS and DHCP running on the server. I’ve run all the Windows updates & virus protection & scans. No other known problems exist. Seems like a DNS problem or something?

Any other ideas??? thanks