To show the queue in sophus, from CLI type:
chroot /var/storage/chroot-smtp /bin/exim -bp
To delete a specific mail type
chroot /var/storage/chroot-smtp /bin/exim -Mrm {mailid}
example:
chroot /var/storage/chroot-smtp /bin/exim -Mrm 1daHZv-000EaR-0A
To see how many mails, there are in queue, you can type:
chroot /var/storage/chroot-smtp /bin/exim -bpc