Best answer by Ken_Griffiths
Your post mentions both a Bridge and Boost, which are two different Sonos products. If it is the Bridge then I would leave that off, but connect/cable a speaker to the network instead. If it is a Boost however I would leave that cabled to the network instead of a speaker.
Having done either of the things mentioned above, try to establish what WiFi channels your router is using and if you know how, fix those channels so they do not change when the router is restarted. Some routers auto-select a channel at startup but usually you can change it to ‘fixed’ in the router configuration pages.
Next goto Advanced Settings in the Sonos App and set the SonosNet channel so it’s at least 5 channels away from your routers 2.4ghz channel. So if your router is set to channel 6, as an example, then put SonosNet on either channel 1 or 11.
Finally goto the App 'Advanced Settings/Wireless Setup' and reset/remove any stored WiFi credentials, if necessary. This will prevent your speakers switching between the Sonosnet signal and your routers WiFi signal.
Hopefully all then will work fine after doing those few things.