Users of our zimbra server randomly complains that they cannot connect to their mailboxes. When we check we see the following errors.
mailbox - Failed to lock mailbox
mailbox - transaction canceled because of lock failure
lmtp - try again for message from=,to=: another mail delivery in progress
lmtp - S: 451 4.0.0 Temporary message delivery failure try again (DATA)
They can login to their webmail and the mails start delivering after a service restart.
zmcontrol -v = 8.0.5.GA.5839.UBUNTU12.64 UBUNTU12_64 FOSS edition
I have tried permission fix but the errors still occur.