I am trying to get my Sonos Beam (gen 1) to show as connected on my Sonos App so I can complete its setup.

On the App I get as far as the Beam showing and sounding and then when the App screen changes it does not show at all (as part pf a system) and so I cannot do the sound setup.  I have re-booted, restored factory settings, tried another mobile, used Ethernet cable connection instead of WIFI, etc. but no joy.

The Beam is connected via HDMI to a smart LG TV and works, but I cannot set it up for the room acoustics, etc. Please can you help?