Audio Drops out after playing computer audio

I am using Cubase 5 on a windows 10 laptop with an Alesis MultiMix 8 as my audio interface. when I initially start Cubase I can use my Akai MPKmini to input MIDI and it plays a VST instrument. If I play audio from my computer,(example YouTube) when I go back to Cubase, I get no sound. At this point I don’t get any sound from any previous tracks I recorded, MIDI or audio tracks included. The computer audio still plays fine but not within Cubase. I have to shut down Cubase and reboot the computer to get the sound back.

What could be wrong?