Emails are not forwarded to the mailbox in Plesk: Permission denied postdrop

Daniel Yordanov

Updated November 19, 2024 19:58

Plesk for Linux kb: technical

Applicable to:

The mailbox jane.doe@example.com is set as a mail forwarder for john.doe@example.com in Domains > example.com > Mail > Mail Accounts.
Emails are not being forwarded to the target mailbox, while an error that is similar to the following can be seen in /var/log/maillog:

CONFIG_TEXT: maildrop/39916.2634847: Permission denied postdrop: warning: mail_queue_enter: create file maildrop/40265.2634847
The plesk repair fs -n -v command returns results that are similar to the following:

# plesk repair fs -n -v
Checking Linux system files
There are incorrect permissions on some items:
/usr/lib64/plesk-9.0/sendmail/postdrop ............................ [ERROR]
- Incorrect permissions on
/usr/lib64/plesk-9.0/sendmail/postdrop. Expected: one of 02755.
Actual: 0755.

Incorrect permissions are set for some Postfix files.

The incorrect permissions must be corrected by following the steps in either of the following sections:

Solution via Plesk GUI

Log into Plesk
Go to Tools & Settings > Diagnose & Repair.
Press Change next to the File System field and set the option to Only the System Files
Press the Check Selected button:
After any issue is detected, fix permissions by clicking the Repair button:
Go to Tools & Settings > Services Management and restart the SMTP Server (Postfix) service since there may be some leftover stuck processes remaining:

Solution via the CLI (command line interface)

Connect to the server via SSH
Execute the command below to fix all the potential issues with permissions:

# plesk repair fs -y
Check if there are any postdrop processes:

# ps auxffw | grep postdrop
root 2703423 0.0 0.0 9092 676 pts/0 S+ 12:59 0:00 _ grep --color=auto postdrop
popuser 2690196 0.0 0.0 97324 4268 ? S 12:38 0:00 | _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2673913 0.0 0.0 97324 4268 ? S 12:03 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2673914 0.0 0.0 97324 4268 ? S 12:03 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2674177 0.0 0.0 97324 4272 ? S 12:03 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2677669 0.0 0.0 97324 4272 ? S 12:11 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2685525 0.0 0.0 97324 4272 ? S 12:28 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2687613 0.0 0.0 97324 4272 ? S 12:32 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2687886 0.0 0.0 97324 4268 ? S 12:33 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
popuser 2688674 0.0 0.0 97324 4272 ? S 12:34 0:00 _ /usr/lib64/plesk-9.0/sendmail/postdrop -r
If they exist, restart postfix:
4.1. Stop Postfix service:

# service postfix stop

4.2. Make sure that there are no stuck processes left:

# ps auxffw | grep postdrop
root 2704157 0.0 0.0 9092 680 pts/0 S+ 13:01 0:00 _ grep --color=auto postdrop

4.3. If they exist, kill hung processes. If there are none, restart Postfix:

# service postfix start