Outlook problem

I recently logged into my Mac with a gmail account that I have had for a while, this account works on my other two devices (phone, and laptop) but when I signed into the account on my iMac it looked like it was brand new as there were no emails present even when I checked the deleted folder, it did not let me check to restore them as there were no emails present to start with, on top of this when I clicked the top right circle with my email initials, the drop down bar showed underneath my name the email address of (outlook_(series of numbers and letters)@outlook.com). How do I fix this?