Hi John,
To narrow down this issue, I would like to collect the following information:
1.Do you sign in to Web Outlook(OWA) on your Mac book via the link http://mail.office365.com/?
2.What browser you are using? Have you tried some other browsers?
3. I would appreciate it if you could give me a screenshot for further troubleshooting.
Additionally, could you try to use your account to sign in to OWA on another computer? If the issue persists, this may be related to your account. I suggest you contact IT and let your IT reset the password for you.
Thanks,
Chris Ni