Hiya @Red lawler have you got a bit more info on your configuration? Is this Exchange Online or On Prem? Are you accessing via Public Internet or via Local network. Are you trying to access using a live.com address? or a company issued credential? etc. (A brief description of your environment and what you have done to try and resolve.
Lots of questions as it really could be any number of things causing your issue. Let me know a bit more info and Ill see if I can help you out!
Best Regards
John