chmod 644 header.shtml chown www-data:www-data header.shtml If page.shtml includes footer.shtml which includes page.shtml , the server will time out. Check your includes for loops. 4. Firewall or ModSecurity Blocks Some security modules block SSI directives (e.g., <!--#exec cmd="..." --> ). Disable dangerous directives in Apache:
location ~ \.shtml$ ssi on; ssi_types text/html; ssi_value_length 512; try_files $uri $uri/ =404;
AddType text/html .shtml AddHandler server-parsed .shtml Options +Includes For security and recursion control, add: view shtml fix
sudo a2enmod include sudo systemctl restart apache2 Navigate to the directory containing your SHTML files or edit your VirtualHost configuration. Add the following:
<FilesMatch "\.shtml$"> SSILegacyExprParser On </FilesMatch> If you cannot modify AddHandler (e.g., on shared hosting), add this to your .htaccess : chmod 644 header
ssi_last_modified on; ssi_silent_errors off; If your SHTML includes other .shtml files, ensure:
location /includes/ ssi on; internal;
sudo systemctl restart apache2 Create a test file test.shtml containing: