This is the mail system at host mta2.blackbaud.com. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. firstname.lastname@example.org :host cluster12.us.messagelabs.com said: 550 Invalid recipient (#5.1.1) (In response to the RCPT TO command. When checking Invalid Accounts in Blackbaud NetCommunity
Try the following steps through resolution:
Verify the email address is correct
Check with email service provider or email server administration for more information on validity of the account.