Sending Route from Garmin APP to GTN750

Hello,

I have a strange problem. I'm using the Garmin Pilot app on a Samsung Galaxy Tab S10 and want to connect it to my GTN 750 in the aircraft via Flightstream. The connection always works perfectly. Everything I enter on the GTN 750 immediately appears in my app as an "update." I can confirm it and see the route on my tablet.

However, I haven't yet figured out why it sometimes fails and sometimes doesn't. I plan a route with Autorouter, receive a PDF, and click the link in the PDF to send it to the Garmin Pilot app. That works, too. I see the route on my tablet. However, I have no way to send it to the aircraft via Connext. The "send" button is simply grayed out. Even restarting the tablet doesn't change anything. If I then enter something directly on the GTN 750, I immediately receive an update on the tablet.

How is this possible?

Thanks!

cu

AH