A website/webmail hosted in Plesk on CentOS/RHEL is showing internal server error 500: Exec format error: exec of /usr/sbin/suexec failed

Symptoms

• A website or webmail is not loading with the error:

  500 external Server Error

• The following error messages appear in domain's logfile or in Apache error logfile /var/log/httpd/error_log:

  (8)Exec format error: exec of '/usr/sbin/suexec' failed
  Premature end of script headers: cgi_wrapper

  ---

  (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server
  Premature end of script headers: wp-login.php

• The following error message is shown on the Home page or reported by Apache configuration checker reports:

  # httpd -t
  AH00526: Syntax error on line 15 of /etc/httpd/conf/plesk.conf.d/webmails/144000m.com_webmail.conf:
  SuexecUserGroup configured, but suEXEC is disabled: Missing suexec binary /usr/sbin/suexec

Cause

File /usr/sbin/suexec is corrupted or missing.

Resolution

1. Connect to the Plesk server via SSH.

2. Rename the corrupted file (if exists):

   # mv /usr/sbin/suexec /usr/sbin/suexec.orig

3. Restore the /usr/sbin/suexec file:

   # cp /usr/lib64/plesk-9.0/suexec/psa-suexec /usr/sbin/suexec

   # chown root:apache /usr/sbin/suexec

   # chmod 4510 /usr/sbin/suexec