As Rharv said, this is most likely because you have 2 programs (RB and WMP) conflicting over which gets to play the wav file. It will probably work if you close RB, then try to open the wav file with WMP. Another way, if you want to stay with ASIO driver, is to "Uncheck" the "ASIO Always On" box. You'll then probably have to close RB, then re-open; it should work from either program after that.

I had this same issue when I was trying to audition realdrum files from within RB. As they are wav files, and my computer was set to play wav files through wmp, they would try to open in wmp but would not play. I finally unchecked the "asio always on" box, closed RB, then re-opened, and voila - I could then audition the realdrums through wmp while rb was also open.

Terry

BIAB/RB 2018 PlusPak. Dell Inspiron23 running Win10, 12GB RAM, 2.5GHz i7, Presonus AudioBox USB interface.