I have several domain names registered and hosted with an ISP (ISP1) in one country. I can collect emails no problems from their POP3 servers. Unfortunately, this ISP does not offer dialup services in the country I live, so I use a different ISP (ISP2) for internet access at my home.
Right up until recently, I've been able to use IPS2's SMTP server (with their account and password credentials configured differently in Outlook XP) to send emails from the domains hosted by ISP1. In fact, this still works for all the domains ISP1 host, expect for 1. Now, when I try to send emails from this domain, I get the following error:
"Reported error (0x800CC78: Unable to send message. Please verify the e-mail address in your account properties. The server responded: 451 rejected: temporarily unable to verify sender address (try again later) <firstname.lastname@example.org>".
This used to work just fine. I've changed nothing. Now I can't sending emails from this specific domain. Any idea what the problem is? Many thanks for the feedback.