I have a Behringer UMC404 feeding two microphones into vMix. I also have internal audio from my computer as an audio input. Everything has worked fine for many years. Recently however, I have had a few instances where during the a live stream there has been a "pop" and the microphones go completely dead. (The music input remains fine and house audio remains good with same microphones) A couple of times I went to the input and reinstalled the same audio source and the mics have come back on. The last time, however that did not work and I needed to drop the stream, restart vMix and and then mics were restored. Any suggestions as to what might be the problem?