Error message on the Home page in Plesk: module unique_id_module is already loaded, skipping

Symptoms

• One of the following error messages is shown on the Home page in Plesk:

  PLESK_ERROR: New configuration files for the Apache web server were not created due to the errors in configuration templates: [so:warn] [pid 55597:tid 140252507555968] AH01574: module unique_id_module is already loaded, skipping
  httpd: Syntax error on line 353 of /etc/httpd/conf/httpd.conf: Syntax error on line 13 of /etc/httpd/conf.d/00_mod_security.conf: No matches for the wildcard '00*exclude.conf' in '/etc/httpd/modsecurity.d', failing (use IncludeOptional if required).

  OR

  PLESK_ERROR: New configuration files for the Apache web server were not created due to the errors in configuration templates: [Wed Mar 21 12:25:31 2018] [warn] module security2_module is already loaded, skipping [Wed Mar 21 12:25:31 2018] [warn] module unique_id_module is already loaded, skipping Syntax error on line 35 of /etc/apache2/modsecurity.d/rules/tortix/modsec/50_plesk_basic_asl_rules.conf: ModSecurity: Found another rule with the same id .

• Apache configuration checker reports one or both of the warnings below ("httpd -t" for CentOS/RHEL-based distributions, "apache2 -t" for Debian/Ubuntu-based distributions):

  # httpd -t
  [warn] module security2_module is already loaded, skipping
  [warn] module unique_id_module is already loaded, skipping

• In some cases, Apache cannot be started.

Cause

The ModSecurity configuration file 00_mod_security.conf contains duplicated records.

Resolution

1. Connect to the Plesk server via SSH.

2. Open the file 00_mod_security.conf in a text editor. The location of the file is:

• for CentOS/RHEL-based distributions:

  CONFIG_TEXT: /etc/httpd/conf.d/00_mod_security.conf

• for Debian/Ubuntu-based distributions:

  CONFIG_TEXT: /etc/apache2/conf.d/00_mod_security.conf

3. Replace "Include" in the lines:

   CONFIG_TEXT: Include modsecurity.d/00*exclude.conf
   Include modsecurity.d/*asl*.conf
   Include modsecurity.d/99*exclude.conf

   with "IncludeOptional":

   CONFIG_TEXT: IncludeOptional modsecurity.d/00*exclude.conf
   IncludeOptional modsecurity.d/*asl*.conf
   IncludeOptional modsecurity.d/99*exclude.conf

4. Locate duplicated ModSecurity modules:

   4.1. Run the command:

   • for CentOS/RHEL-based distributions:

     # grep -ir security2_module /etc/httpd/ && grep -ir unique_id_module /etc/httpd/

   • for Debian/Ubuntu-based distributions:

     # grep -ir security2_module /etc/apache2/ & grep -ir unique_id_module /etc/apache2/

   4.2. In case duplicates as shown below are found:

   # grep -ir security2_module /etc/apache2/
   /etc/apache2/conf.d/00_mod_security.conf:LoadModule security2_module /usr/lib/apache2/modules//mod_security2.so
   /etc/apache2/mods-available/security2.conf:<IfModule security2_module>
   /etc/apache2/mods-available/security2.load:LoadModule security2_module /usr/lib/apache2/modules/mod_security2.so
   
   # grep -ir unique_id_module /etc/apache2/
   /etc/apache2/conf.d/00_mod_security.conf:LoadModule unique_id_module /usr/lib/apache2/modules//mod_unique_id.so
   /etc/apache2/mods-available/unique_id.load:LoadModule unique_id_module /usr/lib/apache2/modules/mod_unique_id.so

   Comment each with "#" in the file 00_mod_security.conf as shown below:

   CONFIG_TEXT: #LoadModule unique_id_module /usr/lib/apache2/modules//mod_unique_id.so
   #LoadModule security2_module /usr/lib/apache2/modules//mod_security2.so

5. Restart Apache:

• for CentOS/RHEL-based distributions:

  # service httpd restart

• for Debian/Ubuntu-based distributions:

  # service apache2 restart

6. In Plesk, go to Tools & Settings > Web Application Firewall (ModSecurity) > Settings tab and click OK to refresh settings.

7. If the error about broken domain configuration appears on the Home page, apply the solution from this KB article.