Website on Plesk returns error 500: Invalid command 'RewriteEngine', or pages for all sites return 404

Symptoms

• Websites that are using the rewrite module for Apache are inaccessible with the HTTP Error 500.

• Error like the following could be found in Apache logs in Domains > example.com > Logs or in /var/www/vhosts/system/example.com/logs/error_log:

  CONFIG_TEXT: [core:alert] [client 203.0.113.2:40913] /var/www/vhosts/example.com/httpdocs/.htaccess: Invalid command 'RewriteEngine', perhaps misspelled or defined by a module not included in the server configuration

• Module rewrite_module for Apache is not loaded:

  # httpd -M | grep -i rewrite

  ---

• Main websites' pages work, but permalinks result in a 404 error, with no log entries.

Cause

Rewrite module for Apache is disabled.

Resolution

Enable rewrite_module module:

1. Log in to Plesk.
2. Go to Tools & Settings > Apache Web Server > Apache modules.
3. Check rewrite and click OK.