Nothing stuck to the build head when you ran your print. The resin window has chunks of cured resin stuck to it. There may be bits of cured debris floating in the resin tray.
|The build head was not properly calibrated||Calibrate the build head properly before printing|
|The exposure was not set high enough in the print settings||In Ember's Print Settings, increase the exposure time for the First Layer, Burn In Layer, and/or Model layer|
|The PDMS of the resin tray has reached the end of its useful life, allowing less light to be transmitted through it to the build plate||Replace the resin tray with a new one (purchase replacement trays here)|
Before running your next print, first you must clean up the mess from the failed print, or your next print will also likely fail. Clean the resin window and clean the resin in your tray. Here are instructions for how to do this.
If you need additional help with this issue, submit a support ticket.