Recently I upgrade my server from Ubuntu 12.04LTS to 14.04.1 LTS. The upgrade went smoothly. However found out later that our email service is not working anymore.

Here are the issues encountered:
1. When user tried to log in via the webmail interface (roundcube) , there is a message that says "Connection to Storage server failed". And the login failed.
2. Whenever I send an email to someone on the mail server, I noticed that it gets stuck in the Postfix Queue Messages. The status message says:
"host jupiter.myserver.com[private/dovecot-lmtp] said: 451 4.3.0 <admin@myserver.com> Temporary internal error (in reply to end of DATA command)"


mail.log shows the following wherever an email was received by Postfix:

jupiter postfix/lmtp[5839]: 4236D10F10: to=<admin@myserver.com>, relay=jupiter.myserver.com[private/dovecot-lmtp], delay=1152, delays=1152/0.01/0/0.01, dsn=4.3.0, status=deferred (host jupiter.myserver.com[private/dovecot-lmtp] said: 451 4.3.0 <admin@myserver.com> Temporary internal error (in reply to end of DATA command))

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/var/log/dovecot.log shows this for failed login:

imap-login: Info: Login: user=<admin@myserver.com>, method=PLAIN, rip=106.186.30.93, lip=106.186.30.93, mpid=5806, TLS, session=<1RL8y4QDjgBquh5c>
Sep 21 04:09:36 imap(admin@myserver.com): Debug: Effective uid=5000, gid=5000, home=/var/mail/vhosts/myserver.com/admin
Sep 21 04:09:36 imap(admin@myserver.com): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=no, hidden=no, list=yes, subscriptions=yes location=maildir:/var/mail/vhosts/myserver.com/admin
Sep 21 04:09:36 imap(admin@myserver.com): Debug: maildir++: root=/var/mail/vhosts/myserver.com/admin, index=, indexpvt=, control=, inbox=, alt=
Sep 21 04:09:36 imap(admin@myserver.com): Error: user admin@myserver.com: Initialization failed: namespace configuration error: inbox=yes namespace missing
Sep 21 04:09:36 imap(admin@myserver.com): Error: Invalid user settings. Refer to server log for more information.
Sep 21 04:10:51 lmtp(5840): Debug: none: root=, index=, indexpvt=, control=, inbox=, alt=
Sep 21 04:10:51 lmtp(5840): Info: Connect from local
Sep 21 04:10:51 lmtp(5840): Debug: auth input: admin@myserver.com uid=5000 gid=5000 home=/var/mail/vhosts/myserver.com/admin
Sep 21 04:10:51 lmtp(5840, admin@myserver.com): Debug: Effective uid=5000, gid=5000, home=/var/mail/vhosts/myserver.com/admin
Sep 21 04:10:51 lmtp(5840, admin@myserver.com): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=no, hidden=no, list=yes, subscriptions=yes location=maildir:/var/mail/vhosts/myserver.com/admin
Sep 21 04:10:51 lmtp(5840, admin@myserver.com): Debug: maildir++: root=/var/mail/vhosts/myserver.com/admin, index=, indexpvt=, control=, inbox=, alt=
Sep 21 04:10:51 lmtp(5840, admin@myserver.com): Error: user admin@myserver.com: Initialization failed: namespace configuration error: inbox=yes namespace missing
Sep 21 04:10:51 lmtp(5840): Info: Disconnect from local: Successful quit

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Postfix config file /etc/postfix/main.cf

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
append_dot_mydomain = no
readme_directory = no

smtpd_tls_cert_file=/etc/ssl/certs/dovecot.pem
smtpd_tls_key_file=/etc/ssl/private/dovecot.pem
smtpd_use_tls=yes
smtpd_tls_auth_only = yes

smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes

smtpd_recipient_restrictions =
permit_sasl_authenticated,
permit_mynetworks,
reject_unauth_destination

myhostname = jupiter.myserver.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all

virtual_transport = lmtp:unix:private/dovecot-lmtp

virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
virtual_alias_maps = mysql:/etc/postfix/mysql-virtual-alias-maps.cf
smtpd_relay_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination

********************************
My dovecot conf file:

!include_try /usr/share/dovecot/protocols.d/*.protocol
protocols = imap pop3 lmtp
dict {
#quota = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
#expire = sqlite:/etc/dovecot/dovecot-dict-sql.conf.ext
}
!include conf.d/*.conf
!include_try local.conf

*********************************************

In closing, these config files were working fine all along and I have not changed anything. I guess there was something in the Ubuntu upgrade that changed something, to break it. I have been working on this for hours but having no success. Any help would be greatly appreciated. Thanks

Ubuntu 12.04 uses Dovecot version 2.0.19 and Postfix version 2.9.1; Ubuntu 14.04 uses Dovecot version 2.2.9 and Postfix version 2.11.0.

It's possible that there are incompatible changes in the configuration files for these. In my experience, Postfix (2.10, 2.11 release notes) tends not to make radical changes (and usually old configuration options are supported). I don't use Dovecot, so can't provide any guidance on that, but the namespace error you're getting might result from some difference in configuration options.

Thanks for your comments. It did put me on the right track to finally find a solution to this problem.
Basically the latest version of Dovecot, its configuration is quite particular about namespaces, which it wasn't in the past. Anyhow adding this to the dovecot.conf file help resolved the issue:

namespace inbox {
inbox = yes
}


Also in the event you have also have an error message that says "Connection refused" when postfix trying to connect to dovecot, within dovecot.conf, uncomment out this line :

listen = *, [::]

This will allow it to listen on both IPv4 and IPv6 interfaces. I had this issue too after I resolved the namespace issue. Hopefully this will help someone else.

i also had a dovecot problem after upgrading to ubuntu 14.04. my imap clients could no longer connect, and i saw these errors in my mail.err file:


i can confirm that adding a "namespace inbox" section with a "inbox = yes" entry fixed the problem.

however, i did not make the raw change to dovecot.conf as sloo did above. instead, i tweaked conf.d/10-mail.conf, where i had read that namespace definitions are "meant" to go (dovecot.conf includes all the conf.d/*.conf files). i uncommented the topmost namespace definition within 10-mail.conf, and ensured that its inbox= line was uncommented and set to yes. now i'm running fine.