Can't connect to any SMTP server
Trying to install Zimbra to replace Outlook on my work machine.
1. test Yahoo account works fine.
2. Gmail account works fine.
3. Exchange account - can't connect to any SMTP server.
I currently use Outlook 2007 as a IMAP client back to Exchange. I also have Thunderbird installed and it too can send email through my employers SMTP server. The set up that works is very simple - port 25 - no authentication as my employer whitelists IP addresses that can use the SMTP server. I can send emails from both Thunderbird and Outlook - but I can't set up the account in Zimbra because the validation fails on the SMTP check with this error message. I tried it as both Exchange IMAP and a generic IMAP account.
Cannot connect to "SMTP server". Please check host/port and network connectivity.
I've tried two different SMTP servers that I verified as working with a test email from Thunderbird. Neither will pass the verification test in Zimbra.
(This is Win XP - Zimbra zdesktop_1_0_build_1537_win32)