Is it showing as connected to the local router? Maybe it needs a firmware update - perhaps see if it appears in the App and will let you do that when it’s wired to the LAN, if practicable.

It is directly connected to my router but does not appear on the app. How can I update the firmware for the Playbase? Only through the app?

Through the app yes. But it’s possible that the desktop app can see the play base and update the firmware if you have a computer to install it on and get it in the mobile app. 

Thank you but no luck with either suggestion. I have not updated my desktop Sonos app and the Playbase is no longer visible as part of my system. Not sure what to do next...Update the desktop app? Purchase a new sound bar for the TV?

Yes Update the desktop app. If it’s there it will prompt for a firmware update. If it doesn’t work I would contact support.

@Aunt Mo have you had any luck? I was forced to update my Sonos app and can’t find the Playbase in the app neither… :/

I did not have any luck...I did call customer service and found out that my WiFi (in the Playbase speaker) is defective.

Will it perhaps work ‘wired’ to your local network?

I tried that as well...no luck with it being wired to the local network. Sonos is replacing the Playbase with a Beam (gen 2). Maybe that is why they discontinued this model?