I have been using my Optec rotator for more than a year without any problems and I find it hard to imagine anyway the rotator could cause a plate solve failure.
First, the "Reverse" option must be correctly set as it tells the rotator which way to move when SGP sends a move command. With the option set to false, the rotator moves in the direction SGP expects it to move.
PlateSolve2 works quite well but does need a pretty accurate hint in RA and DEC and plate scale -- and a reasonable focus. If any of these are off by a significant amount ( 10 arcminutes ), the solve will likely fail.
First check that your pixel scale (in control panel / camera) is accurate. Then you need to make sure your scope's position and your rotator's position are accurately sync'd.
At start-up, manually slew the scope to somewhere near the zenith, get a decent focus. Use the "Solve and Sync" procedure to do a plate solve, which will automatically update the RA, DEC of the scope and sky position angle of the rotator. This initial Solve and Sync may very well fail with PlateSolve2 and I don't think there is an automatic fail over to Astrometry.net (or ANSVR). This will require you to repeat the Solve and Sync with the blind option.
After this, if your scope is well polar aligned and OTA is reasonably orthogonal, PlateSolve2 should work the rest of the night. However, there are times when PlateSolve2 may still fail (should be rare), so a fail over to Astromentry.net (or ANSVR) will occur.