When signing in to SendPro Online, the message "You have not completed your account registration" appears.
The username being used is not active.
In the message, there is a "Resend email" option. Select Resend email to resend the registration email. Follow the prompts in the email to activate the SendPro account.
If you do not receive the email, check your spam/junk email folder. The email comes from firstname.lastname@example.org.
UPDATED: January 04, 2021