If your Fellow Chrome Extension has suddenly stopped working, it may be related to a setting in the latest version of Chrome (Chrome 90). This setting blocks third party cookies which causes Fellow's Chrome extension to stop working.
Good news is that you can get the extension working again by following these steps: (You'll still block third party cookies but will need to whitelist some site urls)
1. Open chrome preferences/settings --> Privacy and security and select “Cookies and other site data” (or navigate directly to chrome://settings/cookies)
2. If you have the option “Block third-party cookies” selected then you can keep it on, but you’ll need to whitelist some URLs.
4. Refresh the Google Calendar / Google Meet page you were on, and Fellow should load again. (edited)
If you're still experiencing issues, please reach out to support!