treadmill Stryd/Garmin Problem

Hello,

Due to the weather, I am currently running on the treadmill. My Stryd connects to my watch (ENDURO 3). I start running....

After running, the running distance is displayed in Garmin, but not in the Stryd app.

I have read that I need to turn off GPS. What settings do I need to adjust so that Stryd recognizes the running distance?

Many thanks

Frank