We are once again running into the below error on a regular basis.  I had a ticket about this a while back which turned out to be an issue with the sftp Time to Live (TTL) settings on your end.  After my last ticket, it worked a little better but we've still had periodic issues with it.  In this most recent integration, it seems to happen about every other day.  Is there anything else that can be done with this?  Can you maybe increase the value a little more so it doesn't happen so often?