I have the Android SimpleSSHD app installed on my phone. From my Arch Linux desktop I can ssh to my phone from the command line. I can also sftp to my phone from the command line.
However, KDE Dolphin refuses to connect.
I have a ~/.ssh/config file with the following content:
Host GalaxyS8 HostName 192.168.1.1 Port 2222 IdentityFile /home/myuser/.ssh/id_rsa
All of the following commands work in the terminal:
ssh -p 2222 -i /home/myuser/.ssh/id_rsa 192.168.1.1 ssh -p 2222 -i /home/myuser/.ssh/id_rsa firstname.lastname@example.org ssh GalaxyS8 sftp -o IdentityFile=/home/myuser/.ssh/id_rsa -o Port=2222 192.168.1.1 sftp GalaxyS8
However, none of the following work in Dolphin:
fish://GalaxyS8 sftp://GalaxyS8 sftp://email@example.com:2222 fish://firstname.lastname@example.org:2222
With the last command, Dolphin reports, "Connection to host 192.168.1.1 is broken." While on the phone, SimpleSSHD reports Pubkey auth succeeded and then Disconnect received. No errors are reported on the phone by SimpleSSHD.
So this appears to be a KDE Dolphin issue. I do not see any messages related to this in the systemd logs on the Arch system.