Yes, I have tried this. The account and machine both work well - BUT, only if the network filter is turned off. At this point, I have exhausted most normal trouble shooting...the problem is something to do with how network filter is configured, but neither reinstalling nor clearing all the rules has resolved it. At this point, I think that Little Snitch may not be long for life on this machine, which is a shame as it has been a great product for me in the past.
My QNAP version is 184.108.40.2065 - so we may be seeing some of the problem here, but that should not explain the network filter issue.
I do appreciate the suggestion though, thanks!