I am trying to connect my android phone with my windows 10 machine. They are connected through cloudflared (CF Tunnel) over WARP. Any other app could talk to the remote machine by using its “local” ip, but not kde connect - it says “could not ping device” even though i am able to ping it myself through the terminal with 0% packet loss. I have enabled multicast 224.0.0.0/4 range in the WARP settings, so in theory it should be able to mDNS through the tunnel. Any other app on the phone could see the remote machine would it be aRDP, Termux or any other app for that matter. KDE Connect is the only one which does not want to cooperate.
What’s your version of kdeconnect? If it is 1.33.0 on an Android phone, you are probably running into a bug described here: Devices don't see each other after Android app 1.33 update
It was 1.33 at first, but after i have discovered the topic you have sent i downgraded to 1.32 and the problem remains.
Have you tried re-pairing both devices after the downgrade?
I did delete the manually added ip address from the android app and then re-added it back in. I could not find the same “add manually” button in the windows version.