I have to continually reset my connect and various speakers to pull them back into the App.   This just recently became a problem,  I feel ever time I open the App different speakers are missing.   

Re-adding the missing speakers to the app is not easy,  in some cases it takes several tries.   I’ve been a SONOS customer for 10+yrs with the same equipment, and I never had this issue until recently (past 12 months).   Wifi in the house is solid, when the speakers are connected I never have an issue with the music cutting out.  All other Wifi devices in the home is working as expected.