More data points
This (error message) occurs with both key authentication and password authentication.
This (error message) occurs when ssh server has UsePAM set to yes or no.
More info...
It now seems that the message "failed to create a new backup channel" happens at the end of every transfer, even after the transfer is successful. As far as I can tell, this message may not be caused by an error, but rather it seems to…
Update:
I changed the following config item in my ssh server's sshd_config file:
MaxSessions 2
...and MAYBE this seemed to fix the problem. I no longer received the "failed to create a new ssh channel" error, but I encountered a different bug:
I…