Updating to Big Sur Beta 9 (released this morning) via Safe Boot solved this issue for me. I had tried literally every fix mentioned. If you're still seeing this issue, do the following: Shut down your Mac Hold the left Shift key and power on Release Shift when able to choose your user and enter your password (if on a corporate owned Mac as I am, you may be prompted to log in again using username and password) Go to Prefs > Software Update Update to Beta 9 and realize that Microsoft Teams notifications have no content, but YOU HAVE INTERNET. Huzzah.