False Jam Error with Envelopes

[FamilyD]

I am trying to print Christmas Card envelopes on the HP M281fdw but this printer keeps producing false 'Jam in Tray 2' error messages.

• I am printing a PDF of the addressed envelopes from a MacBook running macOS 10.14.6.
• Envelopes are typical envelope stock with dimensions 7.25" x 5.25" (for 7x5 Cards).
• I was able to print the first 'test' envelope fine from the 'Priority Tray'. (I presume this is HP's new name for the 'Manual Feed Tray' and what HP considers to be the 'Tray 1' on this device)

However, when I put even just one envelope into Tray 2 (the main paper tray), in order to not have to manually feed all of the envelopes, I get the 'Jam in Tray 2' error. I have opened Tray 2, Tray 1, the back enclosure. There is NO JAM anywhere. No envelopes or sheets are missing. NOTHING JAMMED. I even switched the paper in Tray 2 to standard letter sized paper and printed right away after the 'Jam in Tray 2' message and... the letter pages printed fine, no issue. There is NO JAM, yet I cannot get this printer to print any envelopes from Tray 2.

It's like the printer is designed to NOT print envelopes from Tray 2, even though the documentation states this is something that should work.

I set the printer settings for Tray 2 to 'Any Size' and 'Custom', to try both of them out since there is no 7.25 x 5.25 setting. Both 'Any Size' and 'Custom' resulted in the 'Jam in Tray 2' error.

IS this printer designed to reject envelopes in Tray 2? Has ANYONE been able to successfully print envelopes from Tray 2? If so, any info about how would be greatly appreciated. Thanks!

[FamilyD]

UPDATE
That first test envelope in Tray 1 (Manual Feed) must have been a fluke. I figured I would just use the Tray 1 manual feed to at least get the envelopes printed, but now every time I try to send an envelope through Tray 1 I get a 'Jam in Tray 1' error. When I open up the Manual Feed tray to look for the 'jam', there is NO JAM. The envelope is sitting there totally fine as if the tray never even tried to pull it. I've tried Tray 1 several times and just like Tray 2, I just keep getting FALSE Jam errors.

Is this printer designed to NOT print envelopes? It certainly seems like it. The printer has been great so far for printing standard letter size paper, but designing a printer to not print envelopes is... very disappointing. I'm hoping this is still just some misconfiguration.

Any help would be appreciated. Thanks.

[FamilyD]

DISAPPOINTING
We decided to just handwrite all of the envelopes. REALLY disappointing. It took a lot to get to the point where we could mail merge all of the addresses into a Google Doc template to generate the PDF of all of the addresses envelope pages. That required writing a custom Google Sheet script to generate the mail merged final document. It took some time, but was successful. That was the 'tricky' part. I would not have guessed that the HP printer we had was the actual weak link in this plan. I guess we had not had ANY problems printing envelopes from our other low-end inkjet or laser printers? I had presumed that HP was a 'step above' and certainly wouldn't have a problem completing a simple task of printing envelopes. It appears I was wrong. Disappointing.