I suggest that you refrain from Factory Reset without further consult. While the Factory Reset might accidentally improve things for a while, it will waste time and will not resolve fundamental issues.

Describe your SONOS system and network for us. Have you changed anything? Are any SONOS units wired to your network?

My system seems to be working fine, so no Sonos issue I’m aware of. However, there really isn’t enough information in your post beyond the fact you have 6 speakers to go on. What happens if you temporarily connect one to your router with an Ethernet cable?

If you did these steps:

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

And checked that your WiFi didn't get an update that changed any of these:

https://support.sonos.com/en-us/article/supported-wifi-modes-and-security-standards-for-sonos-products

Then wiring one to see if it helps is a good first step. The diagnostic and support call a second.

Don’t hit me… but until now nobody mentioned the most forgotten thing you always should try first.

Restart of all network, controller and Sonos devices. Unplug… plug in…

And check for updates for Sonos controller and firmware. 
 

Thanks, my sonos is fixed and working correctly. Furthermore, you guys wanted to having interest in the General knowledge groups then join this gk whatsapp.