First of all, thank you for this app, it helps a lot.
1. Being logged off
2. Click on "Start timer" in Redmine. That opens a popup to log in
3. Log in into Tmetric with a Google account "A"
4. Realizing I am logged in with the wrong Google account.
5. Stop timer
6. Logoff from the Tmetric web app
7. Log in with the Google Account "B"
8. Start timer => "Forbidden"
To resolve the issue, I completely close Google Chrome and start it again.