SONOS APP STILL SUCKS

Try the update process and then verify all devices are on the latest software/firmware.

Power down ALL Sonos, reboot the router and Controller then power up the Sonos.

Check the FAQ for WiFi issues

https://support.sonos.com/en-us/article/improve-your-sonos-products-wifi-connection

Last resort call Support as with all the latest updates things “should” be better for you.

Sorry, this house runs 24x7 with internet & wifi connectivity. Sonos’ 1990 approach that included “REBOOT THE ROUTER” longer makes sense. SONOS needs to do better. Frankly running around my house powering all my SONOS devices off and on itself is a chore, they are not always an arms length away. I’m going to do one thing. Uninstall the app on the Galaxy and reinstall it.  The apps UI behavior cannot possibly be tied to a network issue. My Windows app starts and responds within 2 seconds.  My IOS App takes a bit longer to respond, but always comes up with the  SONOS system intact - UI still sucks.

Then set up all your Sonos devices with reserved IP addresses, following the instructions in your router’s manual. It’s a more ‘permanent’ solution that does the same thing as the process mentioned by ​@Stanley_4 . 

None of the other devices you mentioned react with your network the same way that Sonos does. 

I have not given up on finding the problem or a solution to it other than the static/reserved addresses. Many hours spent with no usable results yet.

I just know that without the IPs set my Sonos are an unreliable aggravation. Ten minutes well spent.

I have my MOVE assigned statically, can easily do that for the others.  But since I do NOT see this problem on the Windows app, but it’s worse on the Galaxy SONOS app, I’m not sure if this will really help; but certainly willing to try it.  The Galaxy app is primarily used  to control the SONOS app stationed near it, so maybe there’s something to that, though its the app that seems to be hunting for the SONOS network.  I have some time today, so I’ll tackle that later.

Done… reinstalled the SONOS app on the Galaxy TAB-A, will see how it goes.

I recently retired a Tab A and as long as it wasn't too close to my Sonos it worked well.

I did have to force-close the App a few times to get back to being stable. Got lazy and just rebooted the Tab.

I’m keeping fingers crossed.   The Galaxy-Tab was the “cheap” way to replace the dedicated CR100 - which was more water resistant!!! especially where this SONOS id deployed.