I tried deleting the computer in Multiplicity, and it shows up (detected) in the available computer list right away.
I add it, verify the configuration (including passcode), test it (gear icon), it passes, but then when I try and connect for real, it fails.
I've rebooted the router, and computers. Multiplicity keeps saying it has successfully connected to the secondary (via its taskbar alert). Everything 'works' except when I try and do a proper connection. Connecting to the second secondary works fine.
As far as I know, nothing has been changed (in Multiplicity or my computers in general). Was working fine for weeks, and suddenly just stopped connecting to the one machine this evening.
I would have to assume it's something with the copy of Multiplicity on the first Secondary PC, since the primary is connecting to the second Secondary fine (so, I'm assuming it's not the Primary software, and the second Secondary's software seems to be working fine, too).
Nothing appears different in the first Secondary's software. I checked everything, even re-entering values just to resave it. Doesn't appear to be getting blocked, even though the behavior isn't really what you would expect if that were the case. The value of the passcode must be stored different in either the Primary or first Secondary, even though they appear correct/same, and I re-typed them on both. Seems like a bogus error, especially considering that Multiplicity repeatedly sees the machine, and even 'connects' to it (taskbar alerts and gear icon test).
Please let me know what to try. I had gone through the Passcode Error section of the FAQ already, before posting.