I have a Sonos Sub - Gen 1, and 2 Play 5 - Gen 2’s.

The Sub will happily connect to both but only produces any sound with one of them - the one not in the room where I need it. Any ideas why a Sub will connect to a Play 5 but not produce any sound?

I could reset and move / rename the speakers but I know this will have a problem with my smart home set up so the ideal solution for me would be to get the Sub producing sound on the speaker I need it to. 

Thanks - and hope someone can help