Why does my iPhone volume go down when I get a text?

Brian has an iPhone 7 and when he's listening to music by bluetooth, and he gets a text, the volume turns way down and stays there. What can he do to stop that? Rich says to do a restart or refresh. There could be an odd interaction between apps. Another thing to try is go into settings, general, reset. Then select Reset Network settings. That will reset your bluetooth. But you'll have to re-pair them.