Remote job upload, however the print not start

Yesterday and today i upload a job with PreForm however the print wil not start. I see the printer is connected and primed,
Therefore, it works many times.
What is the problem and what can i do?

This happened to me recently, and it was because the setting for resin type in PreForm did not match what was in the printer. The print showed up on the screen and I forced it to start and it immediately complained about the mismatch. I slapped my forehead and re-primed it and did it over in PreForm with the right settings and it worked.