Hotmail

I had to get a new password for my hotmail yesterday.  a notification popped up on my phone which said "unable to sign into Hotmail"  I had not been trying to do that, I was having a phone conversation.  When I finished, I tried on my phone to access my email, to no avail... So I tried my computer and the same thing....the password was wrong.  I had been using this password for a long time.  I made a new password and I can now get in..  But I am confused as to why this happened in the first place.  Does this mean my account my have been compromised?