How can I stop all the unauthorized login attempts from around the world?

Assuming he hasn't exposed the alias it's possible they could be generating possible variants and attempting logins to see which succeed in a response.

Whether or not that's the case two things need to happen, and it's worrying that MS haven't addressed this.

When Microsoft detect these regular constant logins from different countries, they should alert the account holder with an "is this you" warning mail and if the answer is no then guide the user to ensure they have at least one 2 factor authentication method set up AND allow/guide/force the user to geo-restrict logins.

If the user wants to use a VPN perhaps they could have the option of choosing a restricted number of different country or countries.

I cannot understand why microsoft have not stopped this, they could easily detect this abuse, in fact they are in the best position of all to detect and stop it.

On a human level whilst 2FA might secure the account it doesn't prevent the user worrying that they are being targeted.

Today, Microsoft support chat checked my account and said it is not compromised. Also, they had me do a sign out of everywhere and said that should kick out anyone else that may have access to my ID's. I guess we will see what happens next! As far as my new priority alias that I created, it was not used to attempt a sign in by hackers for a week or so after I created it, then they started trying unsuccessfully to sign in with it after one week. I only used it after creating it once to sign to my Microsoft and email account, which is it! After signing in and using my secondary pin I never used it for anything else. I continued to use my old email address that was my old sign in ID before I created the new priority alias! They have never been able to gain access to my account but at first, they were trying many times a day unsuccessfully using my original sign in ID. and now they are again using my new alias. According to Microsoft support my account is safe. Again, I signed out of everything using the link Microsoft Support provided to me today. Hopefully, it will stop now! Thanks for all the advice and help everyone.

yes I am baffled!

What I want to know is how in the heck do I have over 100 sign in attempts from around the world from over 40 different countries and IP addresses with in the last 30 days and got no type of notification ???? No security alert, nothing!!! What is going on? This is why I cancelled my 365 account because it didn't feel safe anymore!!!

Me too ! And the link says not you , secure your account, you click it and it says login was unsuccessful no need to secure your account... bs!!! How about they do simple things like lock the account after so many attempts!!!