I am affected by this bug too. When I choose connect to network from left bar, it open a connection dialog, after giving the credentials it open a new tab with sftp url but shows "Unable to mount, could not connect to the server for this folder".
But if I open nautilus after that, I can directly access the sftp link(without any password). That's means sftp was established earlier by Pantheon-files.
I am affected by this bug too. When I choose connect to network from left bar, it open a connection dialog, after giving the credentials it open a new tab with sftp url but shows "Unable to mount, could not connect to the server for this folder".
But if I open nautilus after that, I can directly access the sftp link(without any password). That's means sftp was established earlier by Pantheon-files.
Additional info:
Files version: 0.2.4
Kernel version: 4.4.0-31-generic
pantheon-files 0.2.4