I'm having the same problem. but I'm using version 7.5.1
Does anyone know what could be the problem?
"Reset by peer" implies the issue originates on the server side but unfortunately that's as much as we can tell from these messages. If you haven't already, take a look at the logs on the DC mentioned above for any related errors occurring around the time frame seen in the MWG logs. If examining the logs on the DC yields nothing, then a tcpdump done on the Webgateway filtered for port 445 is should definitely tell you more.
For details on this and other t-shooting tips regarding DC connectivity, refer to: