Few mails are not reaching to a recipient while other are receiving the same email

Hi

I am facing very strange issue for few days. 

The email sent by a user to multiple internal recipient, is not reaching to one recipient, while others are receiving that email.

Few users are facing this issue. mail neither reaching in their inbox nor Junk folder.

I am using Exchange Server 2013 CU2 and TrendMicro MailScan anti-spam.

I have searched the logs in TrendMicro Mail Scan but nothing found.

Please help.

Thanks,

Manoj 

Thanks, Manoj