Environment: Windows 2003 SBS, all current patches and updates. Exchange is used for internal mail only, and POP3 used for external mail. Connection is via a somewhat slow wireless ISP.
Outlook 2003 on multiple client computers, using POP3 to send/receive email to hosted email domain. Can receive mail fine, but outgoing mail fails. When testing email (within Outlook email accounts), two errors appear:
Send test e-mail message: The specified server was found, but there was no response from the server. Please verify that the port and SSL information is correct.
Find outgoing mail server (SMTP): Outlook could not connect to the outgoing mail server (SMTP). The problem could be the server name or port, or your server may not support SSL. Verify your port and SSL settings..."
This issue is the same for all computers at the site. The same email server is used for incoming POP3 and outgoing SMTP traffic. Webmail works from this site.
Off-site, we are able to send/receive mail without any problems. AVG AntiVirus on the server and on the client PCs is set to check incoming mail only, not outgoing mail.
No changes have been made to any firewall settings, yet outgoing mail is blocked. The Outlook client can find the SMTP server, but does not receive any response. Any ideas?