Grabbed this out of the WinSCP log file, looks like there's an error at the CLI prompt causing the issue.
. 2018-09-18 14:40:51.229 Access granted
. 2018-09-18 14:40:51.229 Opening session as main channel
. 2018-09-18 14:40:51.233 Opened main channel
. 2018-09-18 14:40:51.236 Started a shell/command
. 2018-09-18 14:40:51.256 --------------------------------------------------------------------------
. 2018-09-18 14:40:51.256 Using SCP protocol.
. 2018-09-18 14:40:51.257 Doing startup conversation with host.
. 2018-09-18 14:40:51.269 Skipping host startup message (if any).
> 2018-09-18 14:40:51.270 echo "WinSCP: this is end-of-file:0"
< 2018-09-18 14:40:51.294 ExtremeXOS
< 2018-09-18 14:40:51.294 Copyright (C) 1996-2016 Extreme Networks. All rights reserved.
< 2018-09-18 14:40:51.294 This product is protected by one or more US patents listed at
http://www.extremenetworks.com/patents along with their foreign counterparts.
< 2018-09-18 14:40:51.294 ==============================================================================
< 2018-09-18 14:40:51.294 Press the
or '?' key at any time for completions.
< 2018-09-18 14:40:51.294 Remember to save your configuration changes.
< 2018-09-18 14:40:51.294 ******************************************************************************
< 2018-09-18 14:40:51.294 ******************************************************************************
< 2018-09-18 14:40:51.294 MPLS NOTES:
< 2018-09-18 14:40:51.294 -PORT DESCRIPTIONS ARE INDICATIVE ONLY
< 2018-09-18 14:40:51.294 -USE LLDP / CDP / EDP TO ASSIST IN IDENTIFYING CONNECTED DEVICES
< 2018-09-18 14:40:51.294 -PHYSICAL PORTS SHOULD BE REMOVED FROM VR-DEFAULT
< 2018-09-18 14:40:51.294 -CUSTOMER HANDOFF PORTS SHOULD HAVE A L2PT PROFILE APPLIED (EPL/EVPL)
< 2018-09-18 14:40:51.294 -CUSTOMER HANDOFF PORTS SHOULD BE LABELLED "UNI"
< 2018-09-18 14:40:51.294 -CUSTOMER HANDOFF PORTS SHOULD HAVE CDP/EDP/LLDP DISABLED
< 2018-09-18 14:40:51.294 ******************************************************************************
< 2018-09-18 14:40:51.294 ******************************************************************************
< 2018-09-18 14:40:51.295 XXXX-PE01.1 # echo "WinSCP: this is end-of-file:0"
< 2018-09-18 14:40:51.296
^
< 2018-09-18 14:40:51.296 %% Invalid input detected at '^' marker.
. 2018-09-18 14:41:06.473 Waiting for data timed out, asking user what to do.
. 2018-09-18 14:41:06.473 Asking user:
. 2018-09-18 14:41:06.473 **Host is not communicating for 15 seconds.
. 2018-09-18 14:41:06.473
. 2018-09-18 14:41:06.473 Wait for another 15 seconds?** ()
. 2018-09-18 14:41:27.704 Attempt to close connection due to fatal exception:
* 2018-09-18 14:41:27.704 **Terminated by user.**
. 2018-09-18 14:41:27.705 Closing connection.
. 2018-09-18 14:41:27.705 Sending special code: 12
. 2018-09-18 14:41:27.705 Sent EOF message
* 2018-09-18 14:41:27.727 (EFatal) **Terminated by user.**
* 2018-09-18 14:41:27.727 Error skipping startup message. Your shell is probably incompatible with the application (BASH is recommended).
! 2018-09-18 14:41:32.898