I've been getting this message via my hotmail.com (now outlook.com) email address several times a day for the last week. I've shared the email below. I believe this to be a legitimate notification from MS as there is a corresponding alert in my login history at account.live.com. This is related to email since it's calling out the POP3 protocol. I initially thought that there might be something wrong with Google as I use Gmail to check my hotmail.com account via POP3 via Gmail configuration. However, that is working fine and appears differently in my login page.
The question I have is that the "unusual activity" appears to be coming from Microsoft. According to ipinfo, 13.101.184.118 is a MS domain in Redmond, WA. Has anyone seen this behavior? How to resolve?
Thanks!