Mail works fine on the Parallels Plesk Panel server, but Qmail tries to stat some messages that cannot be found and writes errors like the below into the log:
qmail: 1179913914.743922 warning: unable to stat mess/21/22265884
Qmail creates several separate message-ID files to handle each message. See the following example:
Each such reference contains specific information related to the message. An error like "
unable to stat mess/22/22265908 " means that this file is absent. This usually happens when the queue has been corrupted due to manual modification or by using the QmailHandle utility.
Missing message files cannot be restored; you can only find such errors in the maillog. Find the files with the given IDs, and delete them one-by-one from the Qmail queue folders. For example:
# find /var/qmail/queue/ -name 22265884 | xargs rm -f
# find /var/qmail/queue/ -name 22265862 | xargs rm -f
Stop Qmail before starting this operation.