Freezing occurs when a bounce message encounters a permanent failure because the sender address of the original message that caused the bounce is invalid, so the bounce cannot be delivered.
Command to view the queue
mailq
OR
exim -bp
View the body and/or header of a queued exim message
exim -Mvh 1XSY5g-0001kh-N6
The following command will remove all the frozen mails:
exim -bpr | grep frozen | awk {'print $3'} | xargs exim -Mrm
or
exiqgrep -z -i | xargs exim -Mrm
