Users unable to send email to office365 users

Hi Team,

We are have Exchange 2013 with Cumulative update 14 in our environment. We have migrated few user to office365 by setting up Hybrid Environment. Now on-premises users are able to receive email from cloud user. But, on-premises users are unable to send mails to cloud users. we have added target address for that cloud user, still not receiving email.

Thanks in advance.