The following steps may help resolve a printer not recognizing a full paper tray or paper jam issue:

1. Check for any obstructions around the tray

2. Clear any paper jam and make sure it is out of the way of the printer

3. Check that all paper guides are correctly placed for the desired paper size

4. Adjust the printer setting to the desired paper size

5. Check that no additional options are activated in the printer settings (duplex, folding, etc)

6. Perform a Printer Reset or Printer Self Test