Dell 2335DN - Manual (Page 247)

3.
Open and close the front cover. 4.
Printing automatically resumes.
CAUTION: If you do not push the duplex unit correctly, paper jam may occur.
Duplex Jam 1
Open the rear door. 1.
Unfold the duplex guide fully. 2.
Pull the jammed paper out. 3.
Return the duplex guide and close the rear door. 4.
Open and close the front cover. 5.