I purchased a premium membership with the sole purpose of uploading Trainerday workouts to my Garmin bike computer.
When attempting to upload ANY workout (I’ve tried mulitple examples) I get the error message “Sorry an error occured. It is likely something specific with this workout”.
Works fine for me. Two things. Make sure you don’t have workouts with a huge number of steps (Garmin supports 50) and make sure you enabled everything on Garmin (disconnect) and reconnect again.
I just logged in as you and sent this workout below and it worked fine. I am sure you see it in Garmin now. I also sent to Intervals with no issue. I am obviously doing indoor / power.