Looking at the log the problems start with an error from the focuser:
[09/01/17 02:55:22.115][DEBUG] [CP Update Thread] ASCOM Focuser: Error in GetCurrentPosition. : Exception has been thrown by the target of an invocation. (System.Runtime.InteropServices.COMException (0x80040402): Timed out waiting for received data)
This was generated by the focuser driver, presumably because of some internal problem.
There are then a series of errors like this:
(System.ApplicationException: Object synchronization method was called from an unsynchronized block of code.)
It's not clear about these but SGP relies heavily on multitasking and so uses synchronisation a lot, it could be that SGP isn't coping properly with the error from the focuser.
It's all being reported from the SGP methods
at qq.id(Boolean A_0)
The names have been obfuscated and will change from version to version but it may be possible to use an assembly decompiler to work out where this is happening.
My guess is that the focuser is returning an unexpected exception and SGP is catching the error but not managing it properly.
This all finishes here:
[09/01/17 03:08:55.476][DEBUG] [Camera Thread] Error in auto focus! Focuser failed to move to the requested position (2205). Focuser reports it is at 0.
[09/01/17 03:08:55.478][DEBUG] [Camera Thread] Adding sequence level notification: Error in auto focus! Focuser failed to move to the requested position (2205).
Focuser reports it is at 0.
Not sure if the focuser has resumed and is giving a valid position of 0 or if SGP has stopped trying to talk to it. In any case several other things now seem to be wrong, PHD2 seems to have lost the guide star and an attempt to resume fails because the image doesn't solve.
A focuser log and a DriverAccess log for the focuser may help.
It's tricky because the focuser was working for hours. It would be really good if the focuser driver problem could be found. Ideally it shouldn't throw an exception. But that's what it should do if it really can't recover and SGP should be able to cope.
Coping may be nothing more than closing down gracefully, reporting an equipment failure.