Hi, Anthony,
My name is Didi. I'm happy to help you today.
Sorry to hear about this issue. I found an article that provides steps to disable device guard on a Windows 10 device at least. If it's your operating system, you may see steps 7-9 of the instructions then try signing in again to Teams.
https://www.tenforums.com/tutorials/68913-enabl...
Disclaimer: The link above is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
Best regards,