Microsoft is easy to work with regarding emails.
Google, on the other hand, is virtually impossible to get to act on something. I was receiving my server messages for nearly 10 years on my GMail account. Then, out of the blue, they started rejecting them. After 3 months of tearing my hair out trying to get them to quit blocking my server messages, I finally went over to Outlook. Not an issue since then.
Any site that tells me I can't use a Microsoft email address doesn't get my registration or business.