If you have logs, we can can give you more insight. In the meantime, here is some general advice for Plate Solve failures:
- Image scale (on the camera tab) has been accidentally adjusted and is no longer accurate
- Mount is failing to sync and the “hint” given to the solver deviates too far from reality
- Plate solve frame exposure was accidentally adjusted and plate solve frames don’t produce enough data for the solver
- Plate solve frame exposure may be in a star poor area at a high focal length
- The filter to use for plate solve frames has been accidentally adjusted to a very restrictive filter
- The search areas parameter was accidentally adjusted and is too low.
I’m afraid I don’t have any great answers about why PS2 would work before a sequence and not during, but you can send logs and we can tell you if we see anything odd. Guidance for sending logs here: How to Submit Logs in SGPro