Syncthing works just fine. I can ping it (over my wifi network), all the machines are on the same 192.168.200.x network.
I have also connected the phone via USB cable and can run adb. The phone is not rooted. but netcat -z -v 192.168.200.239 1714-1764 returns netcat: connect to 192.168.200.239 port 1714 (tcp) failed: Connection refused for every port. Everything I found on the web implies a firewal issue, but I have no firewall inside my LAN. The phone runs android 7 (a Samsung galaxy S6) and I routinely synchronize contacts, calendar and to-do list (Korganizer and Kaddressbook - Debian 12.12) with my own radicale server on the FreedomBox (Debian 13.1). What I really want is to run kdeconnect-SMS to send/receive texts from KDE. Any suggestion? What am I missing? Thanks. Augustine

