It turns out that DNS or getaddrinfo calls were failing to resolve myreviewboard.mysite.com
It really helps to enable the logging features in Reviewboard and set their output to Debug level of verbosity, when Reviewboard is doing something wonky.
At another question here on Stackoverflow, it was recommended that ReviewBoard may not be able to read certain mercurial repository versions and that a clean clone (hg clone -U oldrepo newrepo
) is required in order to get it to work in ReviewBoard. I'm including that tip here in case it's not some other thing.
But basically without the debug logs on the server side, a client-side error # 207 is impossible to debug.