Adobe Reader DC crashes MS Outlook

Windows 10 Pro

MS Office 2016

Adobe Reader DC v 2020.012.20043 (updated)

I click on the "mail" icon to email a pdf as an attachment and send the email via Outlook. When I go back to Outlook to send another email, it will not work. It's locked. No error message. 

Once I close Adobe, then Outlook will work properly.

Please assist.