Don’t Factory Reset without further consult -- you are wasting time because the Factory Reset will not cure fundamental networking issues. A simple reboot of the SONOS system will often cure this sort of issue. Briefly flipping the iPhone to Airplane mode might work around a temporary connection issue.

Describe your network for us. What is wired? Which router are you using.

If you have not already done this you should “reserve” or “fix” the IP addresses of regular network clients. Most routers allow this, but you may need to dig through some documentation.

Thanks buzz..can’t see how that helps?

Everything else works just fine..

3 and 5 to router (BT latest 2020) and to Mac are all just fine.

3 and 5 to iphone 12 all just  fine...except when power cut or switch off 5. It then does not get found by iphone. It reconnects immediately to Mac but iphone cannot find it.

I then play the 5 on the Mac and then instantly re-appears on the iphone.

Add to this I’m not computer expert so “fixing IPs” is out of my league and I had hoped `Sonos designed their software to take that in mind.

This is a complex issue that is not practical for SONOS to prevent. As networks become larger and more complicated, similar issues can develop with other products. The disadvantage for SONOS is that there is too little time to react to network issues because music must play in real time.

Anyway, you should submit a diagnostic within 10 minutes of one of these events, then post the confirmation number here. SONOS staff can view the diagnostic and comment about what they find.

If you call SONOS support they will be able to identify issues and may be able to help you reserve IP addresses.

Had gone through that thread and attempted the entirety to no avail. However I just found that my son had used the Home app site on his iPad to discover gadgets consisting of the speakers.