php - include header page session error

I have a header page which includes navbar and necessary css's, js's.

I'm trying call the header page from contact page but there was something going wrong.

I take this error on the contact page.

• Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at C:\xampp\htdocs\test\includes\header.php:84) in C:\xampp\htdocs\test\contact.php on line 3

following the contact page codes.

include_once ("includes/header.php");
session_start();
require_once'includes/phpmailer/security.php';
?>




    


        
        
message sent
        
        
        
message failed
        

        


            

                Your Name *
                >
            
            

                Your Email address * 
                >
            
            

                Your Message *

                >
                
                



                
            
        

    

header.php folder path--> C:\xampp\htdocs\test\includes\header.php

contact.php folder path --> C:\xampp\htdocs\test\contact.php

Answer

Most likely issue is that the includes/config.php or includes/header.php is outputting something to the browser - probably white space.

If these files have a closing PHP tag ?>, removing them should help solve the issue. Also make sure none of the files are using echo or print or other output functions.