I suspect others have seen this occasionally but sometimes, randomly, PS2 just will not solve. It also will not stop trying and I often have to shut down SGP with the task manager. Virtually every time this happens it will solve with an astrometry.net blind solve just fine.
What would be nice is to be able to have it look at far fewer regions before it goes to astrometry.net. The current minimum is 100 but I have found if it does not solve before 10 areas with PS2, it never will.