You released a quarantined email but the mail is still not delivered to the intended recipient. Upon checking the mail tracking logs of HES/TMEMS, you see that the mail was either quarantined again or deleted.
This occurs when there is more than one policy preventing the mail from being sent. Thus, if one policy quarantined the email the first time, the other policy may catch it when it is resent, either deleting the email or putting it into quarantine again.
To resolve the issue, check for other policies that may be catching the email, and disable them before resending the mail.