A user’s account may be locked if it has been compromised.
If you have given out your username and password to an unknown party, it can be used for email spamming. Email spamming from the university could lead to us being blacklisted on spamblock-servers. This, in turn, means that legitimate email from the university to sites that have us blacklisted won’t go through. This can be anyone from Yahoo to Comcast to other universities.
Please remember, no one should be asking for your username and password via email.