Doc ID 2109555.1 discusses this error in the context of OSB and recommends Patch 22277236 to upgrade to Maverick 1.4.44.
Does this remedy also apply to MFT?
Note, may not apply to my case. I'm using MFT Source - sFTP Remote with Authentication Type = Password (Private Key None).
I have confirmed that the remote sFtp service is configured correctly for the user initiating the session.