Article ID: 114260, created on Jul 2, 2012, last review on Aug 12, 2014

  • Applies to:
  • Plesk 11.x for Linux
  • Plesk 11.x for Windows


A subscription has a mailbox with a name containing uppercase letters, such as "MailBox@domain.tld." After upgrading Parallels Plesk Panel to version 11, the customer cannot log in to their mailbox with the mail client due the error user name or password is incorrect.

In the mail log (/usr/local/psa/var/log/maillog), you can find these errors:

Jun 29 07:04:39 hostname /var/qmail/bin/relaylock[1423]: /var/qmail/bin/relaylock: mail from xx.xx.xx.xx:51844 (not defined)
Jun 29 07:04:39 hostname smtp_auth: SMTP connect from unknown [xx.xx.xx.xx]
Jun 29 07:04:39 hostname smtp_auth: FAILED: MailBox@domain.tld - password incorrect from (null) [xx.xx.xx.xx]

Jun 29 07:04:45 hostname imapd: IMAP connect from @ [::ffff:xx.xx.xx.xx]ERR: LOGIN FAILED, ip=[::ffff:xx.xx.xx.xx]
Jun 29 07:04:45 hostname imapd: 1340969618.427148 DISCONNECTED, ip=[::ffff:xx.xx.xx.xx], headers=0, body=0, rcvd=0, sent=59, maildir=/etc/rc.d/init.d


Parallels Plesk Panel 11 converts the mailbox name to lowercase letters during the first mailbox modification after the upgrade. This conversion is done due to numerous problems with mailboxes whose names contain uppercase letters.

#113752 Email addresses containing capital letters do not work


Replace uppercase letters with lowercase letters in the mail client configuration. After that, you should be able to connect to the mailbox.

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