Configuring preferences and options in Outlook.com
If this helps, I got this email all the time. And when I disconnect and reconnect, eventually the emails would return.
What I have done is I have turned on 2-factor authentication on my Google account (and on my Microsoft account because it's a good practice). and that has eliminated the emails ever since.
Yes, you will need your mobile device to assist you into logging into your computer or other device the first time but you can be assured that your account(s) will only be logged in by you.