Hi @Steinmetz, let me see if I can help out here!
Your post has been translated to English as this is an International forum, please post any replies in English and it will be easier for me and other users to assist you.
Could you possibly elaborate your question a bit? Does the app shut down after you have entered a call or does the screen go black after you have entered a call?
There is a sensor at the upper part of your display which detects if your ear is within proximity or not, and if it is then your display will go dark during calls. This is to avoid you accidentally ending calls with your cheek for example.Do you have a display protector mounted on your device, or any cover which could cover the sensor?
Please do elaborate and I will do my best to assist you!
