How do i get sendmail to process mails in /var/spool/clientmqueue? sendmail -q does not work for this directory.
You will need to check what items are in that folder, if it is a qf/df pair, then it probably a failed mail transaction. So something wrong with your setting or mail not going out or to someone or even got rejected.
You also need to know that the normal "sendmail -q" will process the queue every one hour interval. You can do "sendmail -q10m" to make it process the queue every 10minutes.
It will also be good to check the mail queue "mailq -v -Ac", see if its empty or not. If its empty, then those mail in the clientmqueue, must have been the one that are not successful.