Do you try to add a new subscription?
If wont work run webupdater (don't run garmin express) and update GTM FW and let us know if your GTM will work.
Add also picture what show Traffic reciver status and subscription when you update FW of GTM with webupdater.

p.s.
You can also try to reset traffic status in uper left corner of screen where you have 3 black lines.