Safesky works well on ground but not in flight!

Hit there,
I was finishing the setup (incl. HEX-adress and other stuff) and start testing safesky on a Android.
On ground beneath the clubhouse and in front of our hangars, safesky shows a lot of trafic on ground and in the air. once take of, there are 0! message about trafic. The display left completely empty of trafic, exept my own.
I use a SIM-Card in this Android 10, build 53.1.A.3.105. This was the case for both of two flights (please check the history of my plane I configured). During the 2nd flight, the sky was full of trafic. We have excellent reception for data com. over 4G and LTE here.
The phone showed well a valid IP4 adress as well as a valid IP6 Adr.
I have used a SIM-Card with unlimited data volume for my country.
BUT: Within this second SIMcard (destinated for tablets and machine communication) there is no POTS- calls possibility. If you are using the phone number or a phone identity, it will goes wrong.

As you neither exept special conditions for the wireless conection nor spefied minimum configuration for this app, I cannot see this as the reason for.

If this is not going to work, I will unsuscribe and go for a classic FLARM Fusion solution next year, instead of a subscription to your solution.

Please check this

COS