Mail form or mail forwarding does not work on Plesk server: execve(/usr/lib/plesk-9.0/sendmail/sendmail.postfix) failed: Permission denied [13]

Symptoms

• Mail forwarding or mailing form on a website hosted in Plesk does not work.

• The following error message can be found in /var/log/maillog:

  CONFIG_TEXT: sendmail[16679]: my_popen(): execve(/usr/lib/plesk-9.0/sendmail/sendmail.postfix) failed: Permission denied [13] sendmail[16679]: Unable to execute MTA

  OR

  CONFIG_TEXT: plesk sendmail[2118]: Unable to save stdin content to temporary file
  plesk sendmail[2120]: cannot create temporary file - (13) Permission denied

• The permissions for sendmail.postfix or postfix-sendmail-wrapper files are set as follows:

  • on CentOS/RHEL-based distributions:

    # stat /usr/lib64/plesk-9.0/sendmail/sendmail.postfix
    Access: (0750/-rwxr-x---) Uid: ( 0/ root) Gid: ( 0/ root)

    # stat /usr/lib64/plesk-9.0/postfix-sendmail-wrapper
    Access: (4750/-rwsr-x---) Uid: ( 0/ root) Gid: ( 0/ root)

  • on Debian/Ubuntu-based distributions

    # stat /usr/lib/plesk-9.0/sendmail/sendmail.postfix
    Access: (0750/-rwxr-x---) Uid: ( 0/ root) Gid: ( 1010/postdrop)

    # stat /usr/lib/plesk-9.0/postfix-sendmail-wrapper
    Access: (4750/-rwsr-x---) Uid: ( 0/ root) Gid: ( 1010/postdrop)

Cause

Incorrect permissions or ownership on the Sendmail binary files.

Resolution

1. Connect to the server via SSH.

2. Set the correct permissions:

• on CentOS/RHEL-based distributions

  # chmod 755 /usr/lib64/plesk-9.0/sendmail/sendmail.postfix && chown root:postdrop /usr/lib64/plesk-9.0/sendmail/sendmail.postfix
  # chmod 4755 /usr/lib64/plesk-9.0/postfix-sendmail-wrapper && chown root:postdrop /usr/lib64/plesk-9.0/postfix-sendmail-wrapper

• on Debian/Ubuntu-based distributions

  # chmod 755 /usr/lib/plesk-9.0/sendmail/sendmail.postfix && chown root:postdrop /usr/lib/plesk-9.0/sendmail/sendmail.postfix
  # chmod 4755 /usr/lib/plesk-9.0/postfix-sendmail-wrapper && chown root:postdrop /usr/lib/plesk-9.0/postfix-sendmail-wrapper