You have to use the user ID and password from work.  UserID will be your initials followed by 5 numerical digits.

If you have not logged in for a while, you might need to change your password.   Try logging in on a work computer and see what happens.

If you still have trouble, there is a direct button on the phones in the office for tech support/helpline.  Read the labels and one is for support.  They will be able to help you.