Richard-UK wrote:
It will work on wi-fi OK if I unplug the Ethernet.
The service order is Ethernet then wi-fi, but the wi-fi status is Amber - can't get them both to green at same time.
The green connection means internet, not Wi-Fi. You can’t have two services connected to the internet. Your Mac connected to internet over Wi-Fi is not necessary for AirPlay, iPhone mirroring, or any of the other services. It must be connected to the same Wi-Fi access point as your other devices. It doesn’t require the wi-fi to be connected to the internet.
Your next post state that you cannot connect to the Internet at all over Wi-Fi (Amber Connect dot without Ethernet connected). That is a problem, but would not prevent AirPlay or iPhone Mirroring. As den.thed noted, it could be a poor wi-fi connection which would be problematic for those services.