No such file, but it is clearly there

I have this line near the top of on of my modules:

require_once ($_SERVER['DOCUMENT_ROOT'].'/application/third_party/phpmailer/src/PHPMailer.php');

but it causes this warning:

Message: require_once(/opt/bitnami/apache2/htdocs/application/third_party/phpmailer/src/PHPMailer.php): failed to open stream: No such file or directory

In the attached screen shot you can see the permissions for PHPMailer.php, I tried changing it to 777 with this:
 sudo chmod 777 /opt/bitnami/apache2/htdocs/sub_crud/application/third_party/phpmailer/src/PHPMailer.php

But my code (which worked fine in Windows) keeps failing on that require_once. Is their a limitation to how long a pathname can be in CI? What is wrong with it? 

Attached Files

Thumbnail(s)
   

proof that an old dog can learn new tricks

Being picky, the PHPMailer.php is clearly somewhere, but you don't show the folder name.

The big clue that I see is that you require
"/opt/bitnami/apache2/htdocs/application/third_party/phpmailer/src/PHPMailer.php",
but you chmod'd
"/opt/bitnami/apache2/htdocs/sub_crud/application/third_party/phpmailer/src/PHPMailer.php".

Do you spot the difference between them? I even indented the above to make it easier to see :-O
Could your DOCUMENT_ROOT be set wrong?