Knowledge Base

Emails are not delivered to the particular recipient in Plesk: marked message to be discarded if not explicitly delivered (discard action)

Symptoms

Emails are not delivered to the [email protected] mailbox on a Plesk server from all or particular senders.
The following message can be found in /var/log/maillog log file:

servername dovecot: service=lda, [email protected], ip=[]. sieve: msgid=20180923061540.Horde.zyLIfVJmZISHx3cXgJ9740t@webmail.example.com: marked message to be discarded if not explicitly delivered (discard action)

Cause

Custom Sieve rule is configured to discard a specific recipient mailbox.

The following configuration exists in the *.sieve file under /var/qmail/mailnames/example.com/john.doe/sieve/ directory:

# Blacklisted Addresses
...
if address :all :comparator "i;ascii-casemap" :is ["From", "Sender", "Resent-From"] ["[email protected]", "[email protected]"] {
discard;
stop;
}

# rule:[.]
if true
{
discard;
}

Resolution

Login into Webmail.
Define the custom filtering Sieve rule:
- For Roundcube: in Settings > Filters.
- For Horde: in Mail > Filters menu.
Modify/remove the rule that blocks some or all senders.

Solution via SSH:

Connect to the server via SSH.
Open the file in any text editor, for example, in vi text editor:
- For Roundcube:
  
  # vi /var/qmail/mailnames/example.com/john.doe/sieve/roundcube.sieve
- For Horde:
  
  # vi /var/qmail/mailnames/example.com/john.doe/sieve/ingo.sieve
Remove the lines containing the discard rule, for example:

# rule:[.]
if true
{
discard;
}
Apply changes and close the file.