When Acctivate is configured to send email through an SMTP service such as Office 365, it will use TCP port 25 by default unless otherwise specified.
Some antivirus programs, such as McAfee, may block communications on port 25. This will cause the error “Failure sending mail” to appear each time a user attempts to send an email from Acctivate.
The solution to this problem would be to modify the antivirus settings on the workstation that is unable to send email by allowing Acctivate to use TCP Port 25. If you continue to have issues sending email from Acctivate, contact our support team for further troubleshooting.