powermta
When sending to Microsoft OLC (Outlook Consumer – i.e. hotmail.com, outlook.com, msn.com, live.com, etc.) domains, are you seeing this bounce message?Microsoft: 5.4.4 (unable to route: no mail hosts for domain)If you’re seeing that error message, or something similar, here’s what’s happening, I think, based on what some smart folks have shared with me.All of those domains have an MX record that points to outlook-com.olc.protection.outlook.com. And when you look up the IP addresses for that server mentioned in the MX record, what do you get? Well, when I do it from here, I get just two IPs: 104.47.58.33 and 104.47.55.33.But other folks showed me examples where they were receiving 25+ IP addresses in response. I can’t reproduce it, so I don’t know if it’s geo-specific, intermittent, or if overall, the whole thing has been addressed. I suspect some combination of all of that. But anyway, I’m told that when the results