YL Mail Verifier is a powerful and easy-to-use solution for the "email message delivery error". with this Mail Verifier, you can easily check every email address from a mailing list and determine if the email addresses are still valid. it does three levels of verification: Syntax, DNS and SMTP. it is the fastest e-mail verifier in the market today. YL Mail Verifier is designed for system administrators, webmasters, programmers as well as for everyone who has his own mailing lists and needs to keep the lists up-to-date.