Ah, that solves the problem. Apparently it is normal that other programs also do not get sound when Jamulus is running. The problem of the error messages has also been solved. They no longer occur. I don't understand why, but I am happy with it. Nice! Then I can now think about making music! Thank you for the assistance.
I just removed Asio4all, which resulted in the error messages below
I just installed Jamulus, and got stuck almost immediately The standard setting for the sound card is ASIO4ALL, but this could be changed into "Yamaha Steinberg USB ASIO". My interface is a Steinberg UR22c, so that could be right. This is connected, en on the moment I get all sound through this interface into my headphone. But as soon as I made this change, all sound disappeared, also the sound of other programs. Does anyone know what's going on here?