Why my prints won’t stick?

Probably it is a build plate leveling issue, make sure your leveling is 100% correct before attempting other solutions.
Also you can try:
– Check if Z=0?
– There may be cured resin in your vat.
– The FEP film may be too tight or too loose. Adjust to the correct tension, or replace.
– Clean the build plate carefully with IPA or other solvents. Dry before use.
– You may be using resin formulated for SLA laser or DLP printers. Try using a known resin.
– Shake your resin in bottle well before using. Also stir resin in the vat.
– Preheat the build plate, also the resin. You can use a hair dryer.
– The build plate may have shifted, too high or too low. Try and level it again, make sure to tighten well.
– The build plate may be defective. Check if the plate surface is flat.