"Error skipping startup message"

Trying to execute shell commands. This used to work on this host.

Getting:

Error skipping startup message. Your shell is probably incompatible with the application (BASH is recommended).

My log is attached.

Version 6.1.2, Build 13797

Happening in 6.3.1 too.
On Windows 10.

Solved. SSH wasn't enabled on FTP login. Had to enable it in control panel

Can you login with an SSH client (e.g. PuTTY)?