Problem using QS on rooted phone

Hello community.
I am using Team Viewer QS on my stock Samsung Galaxy S7 without any problems:
But starting the QS app on a rooted S3 LTE (i9305) running Lineage OS 14.1 (Android 7.1.2), this information box pops up:

Since I do not know the original English text, my own translation is:
"Remote controlling this device.
This device supports the additional function "Remote Control".
For further information please contact our support."

Because I am using the free version (for supporting my dad), I cannot create a ticket.
Therefore, I hope someone here can help me.

Greetings
Matthias