Error occurred while trying to create a mail document

Hi

I am experiencing an error when pressing "Send as attachment" in Adobe Reader. I get the error "An error occurred while trying to create a mail document. Adobe Acrobat is unable to complete your request".

Adobe Reader 19.008.20080

Office 16.19.0 (Build 18110915)

Mac OS High Sierra 10.12.6

I have tried the following but it didn't help

- Delete "Send Mail" folder

- Resetting Adobe Preferences

- Added Home folder to "Security (Enhanced)" tab

- Set Outlook as the default mail application under "Email Accounts"

- Reinstalled Adobe Reader

- Reinstalled Office 2016

If I preview the PDF and click open in "Adobe Reader" and then click "Send as Attachment" it attaches and works the first time, but the next PDF I try it on sends Adobe into a "Not Responding" state. Then I have to force quit before Adobe can be responsive again. If I downgrade to Adobe Reader X and XI it goes into a  "Not Responding" state when I click "Send as Attachment".

Any help will be appreciated