delete sharepoint

I used to be able to open my work emails on my iMac and use Microsoft programs such as SharePoint, but my company no longer allows that. However, this has left me with a legacy issue I need help to fix.

Every ~15 minutes I get this password prompt that I cannot complete. I don't have the password and am unable to reset it, so I have to hit 'deny' about 8 times (it progressively rolls through various stored info locations after 'adalcache') to get rid of the prompt. Any ideas??? It's driving me nuts!!