Screen sharing using iMessage to initiate

[davehutch]

Hi all, I have an Intel 2015 MBP and my wife has two machines. On her 2015 Intel MacBook running Big Sur, I can share and control the screen using iMessage to initiate a screen share. Everything is fine.
I should add we are both on the same WiFi network at home.
However, when we try the same thing on her M1 MacBook Pro it says it can't connect and I should check my firewall but that is switched off on both Macs.

The connection works for only 2 or 3 seconds and then disconnects.

Any ideas what might be causing the problem please?
Thanks

 

[davehutch]

OK, managed it. For some reason I had to enable Screen Sharing in Prefs on both machines. Then when I switched it off again it continues to work. Problem solved.