HP Laser Jet Pro M501 jams on first print session.

[herewego2]

Upon duplex This HP Laser Jet Pro M501 jams on duplex during the first print session.

Once the paper is cleared, then duplexing is possible. 

A HP authorized repair office could not identify the problem ("I cannot witness the jamming," he said). 

Can I get store credit for the value I paid for this item to trade in?  Plus I got an extended ink cartridge new in box that is worth several hundred dollars

[Valsimot]

Where does the leading edge of jammed paper stop when a duplex jam occurs?

[herewego2]

The paper stops after it comes through the feeder. The paper arrives 10% through and stops.

[Valsimot]

Can you open back cover and take a photo of jammed paper and post it here, it's probably a simple fix

[herewego2]

First photo is the back door. The second photo is the top section. I appreciate your following this matter. Thank you for your continued research to diagnose and correct this problem. 

rear viewtop view

[Valsimot]

I would remove the printer back cover ( 2 screws) and duplex and inspect the paper guides with a tip of a finger to check are they smooth. Sometimes if there is a small damage or crack in the paper guides a sheet can jam on that damage, and it's possible to feel it under the tip of a finger.

[herewego2]

I removed the two screws, removed the back panel, checked the back, and checked the duplexer on the front (after removing the cartridge). 

The 2 photos show that. 

There were no cracks or damage.
Then I printed. 

Subsequently, it jammed again. My photos to show the jams are below (3 in total).

Please advise. 

https://share.icloud.com/photos/0deAdkN7s7rrbJimrnTycfx-w 

https://share.icloud.com/photos/013CWi0ZzM_uKluVrePNkLT5A

https://share.icloud.com/photos/0cfXGvbG5Zrn-Jg0L6wu2V7SQ

https://share.icloud.com/photos/0e34L9EOJ6GA6KLtv6j185Vlw

https://share.icloud.com/photos/082cdMIiC1qh0S-_upRBAVhHg

[Valsimot]

Check the leading edge of the sheet that jams, and inspect paper guides near the leading edge.

Does it jam when you print from tray 1?

[herewego2]

Ten days later, this printer still jams on ALL duplex jobs. The edges are not damaged. 

Did you say that this would be a simple fix. Please assist with a video conference. 

[herewego2]

Please send me information how to trade this duplex-broken printer in for a new functioning office laser printer. I have ink that I need credit for, too. 

I have not heard from you after trying each of your suggestions.