just to make sure i understand:
Your animate.php page sends an email to your email address using Universal Email, you have configured your email address to automatically respond to incoming emails, but this does not work sometimes?
If that is the case the problem is on your inbox, not in the univerrsal email code.
Universal Email will only pass the email message onto the SMTP server, the SMTO server delivers the message to your inbox, your inbox handles the auto response,