If you are receiving an "Unexpected Error" in Gmail when trying to Tout an email, you probably need to do a reset on your gmail connection.
Reset Gmail Connection
1) Go to your Settings > Email Tracking > Manage
2) Click Disconnect from Gmail
3) After disconnecting, click Connect to Google
Once you are reconnected, go back to Gmail and refresh your page and try Touting your email again. If this doesn't work, please submit a ticket to our support team at toutapp.com/help