Is your sendobject function configured to edit the message before sending? If so, does Thunderbird open in edit mode?

Thanks Stans. I set 'edit' to on and now I get runtime error 2046 coming from the sendobject function. Google found this https://answers.microsoft.com/en-us/msoffice/forum/all/microsoft-access-2019-run-time-error-2046/94683fc1-d380-4191-9f7e-6361f44e2619 . Answers seem to scold me for not using Outlook. Perhaps Access2019 is missing something. I do have Microsoft 'Mail and Calendar for Windows 10' loaded.

What the only available official documentation on the sendobject function says is that it uses MAPI, simpleMAPI to be specific. It is also documented that extendedMAPI support is added only after installing Outlook, and that extendedMAPI was intended for communicating with Exchange servers, but this was deprecated in favour of EWS, which in turn is getting abandoned for MS Graph. I can't find any documentation that indicates the lack of simpleMAPI support in Office 2019 apps, or the need for extendedMAPI (added and/or used by Outlook) by those apps either. This lack of documentation is a problem and cause of confusion. It seems MS would rather not tell you that Office 2019 apps won't simply work with simpleMAPI, and that extendedMAPI is required, and by extension Outlook is also required to add extendedMAPI, or that the MAPI implementation in Office 2019 won't work with any other client except Outlook. You could get in touch with MS Support about MAPI in Access 2019, but don't expect support from them regarding third-party clients. The thread you linked to has an alternative to sending Access objects via Tbird. I strongly suggest you adopt it.

Thank you, I will try the suggested code.