This is not uncommon. Remember, when you sign in to (or install) Office 365 on your computer, no matter what computer type it is, ALL computer store your login credentials or a "security token" to help identify "where" and who you are-- not necessarily geographically but security-wise. This is how a company that offers software services on the internet (other services do this too; Gmail, Yahoo, etc.) try and make sure they can tell if someone is pretending to be you from somewhere else!
This intrepid IT guy received a notification from one of my web services one time that they had automatically blocked an attempt to access my account from Uzbekistan! How did they know it was probably not me? Well, I may be intrepid, but not that intrepid! Someone had found out my password but they were blocked from my account because of "where" they were. Thank goodness! So, we don't want this little service to go away but sometimes we need to work around it a little bit...
The 'Browser Sign in Hassle"
Is your browser having a hard time signing you into your Office 365 account because one of your kids has saved their password info on your computer? Or, do you have a school Office 365 account in addition to your family one from MCA and Office Online can't seem to "pick the right one" when you are signing in? Here is what you should do:
1. Remember, the best way to avoid some of these conflicts (and keep your account secure from little eyes or accidental emails from the wrong account) is do NOT save your passwords into your browser. Sign in each time or use another password manager to keep your accounts apart. (There are several thrid parties out there that store your passwords for free.)
2. If you would rather not, then here are some helpful steps from Microsoft to switch between accounts:
Switch between accounts, such as a personal account and work or school account:
If you're already signed in with your Microsoft account and you want to sign in with your work or school account instead, or vice versa, do the following:
Sign out of the account you're signed in with, and then sign in with the other account.
- OR -
Open a private session in your web browser. For example, in Internet Explorer or Edge, use InPrivate; in Chrome, use the incognito window; or in Firefox, use New Private Window.