In Compass 1.15.0 on Mac OSX when using SSH tunneling, failing to provide the password for Username/Password authentication causes the port validation for the SSH tunnel to incorrectly report a missing port number. Refer to the attached screenshot.

The user experience problem may be exacerbated by the flag for the missing password not being visible due to having scrolled above the top of the window. See COMPASS-3039: Poor user experience due to vertical scrolling in the Connect to Host dialog.