There may be black spots on the screen due to liquid leakage, the area can not be properly exposed; there is solidified dirty resin on the screen that affects the release.
Cause 2: Resin
The resin itself is easy to produce bubbles, there will be a small number of small bubbles appear in the top of the model, you can try to pad a corner of the printer to play a role in eliminating bubbles in the printing process.
