Are you using New Outlook?
I just performed 2 tests with Old Outlook (one with the EditMessage parameter set to True, the other with it set to False) and it worked fine. I don't have New Outlook.

volgen :)

Here's how to tell what version of Outlook you have: What version of Outlook do I have?

I've been asked this A LOT, so a video is forthcoming.

When I open Outlook, I'm seeing a "File" selection on the menu bar BUT I did recently go through the MS routine to run the New Outlook.  However, when I click the Outlook icon on my Desktop, the version that opens has a "File" selection on the menu bar.

Also, the "Try the New Outlook" selector button is set to "Off".

Interesting. Could be an issue with your code. Could be NEW Outlook installed something that interfered with OLD Outlook. I'm not sure. I've never run NEW Outlook before. I would recommend UNINSTALLING NEW Outlook and then if the problem persists, UNINSTALL and REINSTALL OLD Outlook. Let me know what happens.

10-4

Uninstalled Outlook New. Rebooted and ran my code with "old" Outlook (installed in 2021).  Same Issue.  Locks up Access and Outlook.  Required a hard Power Off.
My Old Outlook program is located in ProgramFiles > Microsoft Office > Root > Office 16 ? Outlook.exe.  In that same location there are several other Outlook files.  I don't know if any are associated with my prior experiment with NEW Outlook:
Outlook.Exe.Manifest
Outlook.VisiualElements.Manifest
OutlookExplorerTellMeZeroTermCommandModel.bin
Outlook Servicing.dll
Outllook Sebhost.dll
OUTLPH.dll
OUTLLRPC.dll
OUTLVBS.dll

I'm not a Windows guy so I'm concerned that if I Uninstall this Outlook version I'll be able to Re-Install.

My Code is:
    DoCmd.SendObject acSendReport, "rptConsignAgreement", acFormatPDF, CustEmail, , , "Your Consignment Agreement from Robert's Golf Shop", "Your most recent Consignment Agreement
             is attached to this email." _
            & "No reply is necessary unless you wish to change the asking price or see an error.  If so, please contact us by reply email or telephone ASAP."    
    DoCmd.Close

Uninstalling and reinstalling Office/Outlook shouldn't be that hard, but that's the BEST way to make sure that any bad/modified files from NEW Outlook are gone.

You could alternately try using the CDO Send Mail code from the Code Vault instead of Outlook. I cover this in the Email Seminar and I'm going to make a TechHelp video on it soon too. It bypasses Outlook and sends directly to your SMTP server. In your case, Gmail.

Just bought the Email Seminar to "smarten up" on the ins and outs of the best ways to send stuff to our customers.  I'm going to take the uninstall / reinstal route as you suggest  Makes sense.  Thanks for your help!
PS:  As an aside, I have discovered that my issue is intermittent just to make it more crazy.  Looking forward to the Tech Help video.

Intermittent problems are the WORST. If I can't reproduce a problem consistently, it's all that harder to fix.

Truer words were never spoken!!  By the way, my problem has been resolved by getting rid of Outlook New and reverting to Outlook Classic.  TIP:  After reverting, I needed to recreate the shortcut on my Desktop.  Took 2 days to figure that one out.  Might want to mention that in your upcomming video.  Thanks for your guidance on this.