What could be causing the SecureSSI error in the PHP script?
The SecureSSI error in a PHP script could be caused by a misconfiguration of the server or a missing module that handles SSI (Server Side Includes). To solve this issue, you can try enabling the SSI module in your server configuration or using an alternative method to include files in your PHP script.
// Enable SSI in Apache server configuration
<IfModule mod_include.c>
AddType text/html .shtml
AddOutputFilter INCLUDES .shtml
</IfModule>
```
Alternatively, you can use PHP's built-in functions like `include` or `require` to include files in your script without relying on SSI.
```php
<?php
include 'header.php';
// Your PHP code here
include 'footer.php';
?>