If you are having difficulty with syncing your workouts with Garmin Connect here are a few things to try to trouble shoot.
First login to your account with your Coach in their Training Tilt platform.
Select "User Settings" from the top right hand menu.
If Garmin is showing as connected click the disconnect button. The follow the guide here to reconnect http://support.trainingtilt.com/articles/1411311-how-to-link-garmin-connect-with-training-tilt
If your data still does not sync then follow these steps.
Login to your Training Tilt account using the web version and select "User Settings" from the top right hand menu.
Scroll down to the Garmin Connect section and click the "Disconnect" button
Login to Garmin Connect on the web version https://connect.garmin.com
Choose "Account Settings" from the right hand top menu.
3. Then choose "Account Information" on the left of the page.
4. Scroll down the page until you see a connection to Training Tilt and click the Disconnect button.
5. Now follow the guide to connect to Training Tilt again here http://support.trainingtilt.com/articles/1411311-how-to-link-garmin-connect-with-training-tilt