After talking with a client who is a customer of MTN in Zambia, it appears there may be some MTN customers with a unique SMTP set-up that requires them to use MTN settings, not ours. This client was unable to use our settings for SMTP, and had to use an MTN IP address for the outgoing server, with port 25 and no authentication or SSL.
If you’re an MTN customer, this may apply to you if you already have an MTN IP address in the outgoing (SMTP) server field in your email’s settings. If that is the case, it’s probably best to leave your SMTP settings as they are. However, the incoming (POP) server settings need to be as described in our configuration documentation.
Just because you are an MTN customer does not necessarily mean that this applies to you, but it’s something to keep in mind if you are.