Unable to connect

Hi everyone,

I hope this is the right place for my problem.
Before posting i have looked at other posts, but none of them seem to fix my problem.

I am running Kodi 16.1 on a windows 10 PC.
When adding a new source from file manager, i get the error “Unable to connect”.
It works with ftp but not with sftp.
It is my own Debian server that i am trying to connect to.
I have tried with IP and with my Domain, but the problem still occurs.

The reason i find this strange, is that i can connect to my server from Kodi on my Android phone and on my Raspberry Pi 3.

But i have now tried from two different windows 10 machines, and it is not working.
Before setting up my own server i was using a seedbox at feralhosting, and that worked perfectly.

I am able to connect to the server with a FTP client and Putty.

I have uninstalled Kodi and reinstalled from scratch.
I have changed my DNS to point at google (8.8.8.8)
I have done the setup on 3 different networks, but i still get the same error.

Any help would be much appriciated.
(Sorry for the spelling, i am Danish)