Hi @Markdon ,
Welcome to our forum and posting your question here!
According to my test on my Outlook for Mac, I can produce your scenario: The Send option is greyed out and add-ins can't lanuch.
Many features of our current products are designed and upgraded based on customers’ feedback. With requirements like this increase, the problem may well be released in the future.
I’ve tried submitted this feature request in my Outlook for Mac. What I can do for you at present is to submit a suggestion for you, and you can also make a suggestion via the Outlook client: Go to Help > Give Feedback.
Thanks for your understanding.
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