Yesterday, several machines at one of our locations stopped sending emails. Outlook keeps saying "sending 1 of n" and will not successfully send. I set up an account in Outlook Express on the server, and it is able to send just fine. I have disabled anti-virus programs; Windows firewall is turned off; There aren't any other add-ins that would interfere.
BUT, if I telnet into the SMTP server and manually type in the commands, I am able to send a messages - even from the machines in question. Therefore, I know it's not an issue with the SMTP server.
Does anyone have any advice? Thank you.