When you set up Calibre Preferences: Sharing by email:
What happened when you used the TEST EMAIL button?
(note: that your firewall/security may need to be configured to allow Calibre to send mail to a different REGULAR email account. It should arrive as an look something like this
Code:
Subject: Test mail from calibre
Date: Nov 22, 2019 10:23 AM
Test mail from calibre
)