Unable to send emails to outside domain through IMAP and POP but able to receive the emails from outside.

Hi,

I have only two Exchange 2013 server in my organization and on each server Mailbox/Client server Role has been installed and DAG is configured, No smart host we are using for security.

Earlier I was facing problem of spam and spoof mails, so I configured open relay on Default receive connector. After configuration of open relay, spam and spoof mails issue was resolved but after that in All IMAP and POP configured users unable to send email to outside domain, but able to receive mails from outside domain. All Users are able to send/ Receive emails through OWA and MAPI.

So only IMAP and POP users not able to send mail to outside domain, Internal is working fine.