Help Squid HTTPS: "Connected, no internet" with android devices devices

[Binson_Buzz]

I have managed to get https filtering working by installing a certificate on my devices.  But, on some of my android devices it says 'Connected, no internet' even though they are connected to the internet.

Has anyone come across this and is there a way to fix?

I have Unifi APs - do I need to install the certificate or something on them?

Thanks in advance