Android 11 seems to be buggy with this I have a Xperia 5 II patched with Android 11 - 1 march 2021
So I have a Zywall 110 setup with VPN server with www.dynu.com name.ddnsfree.com so that it only allows by a given IP on the firewall which my phone has the dynu app to update the IP I'm on over 4G...with me so far?
If I reboot my phone and don't update the IP for name.ddnsfree.com that the firewall on my Zywall is allowing I get connection failed...Ok thats meant to happen so a run the dynu app on my phone to update the IP try connecting the VPN again and not only does it fail I see no traffic to my VPN server.
At this point your think you have not set it up right but wait theirs more!
I reboot the phone run the dynu app to update the IP I'm on over 4G then connect to my VPN and it works!
