How to fix "Headers already sent" error in PHP
Asked 07 September, 2021
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When running my script, I am getting several errors like this:


  

Warning: Cannot modify header information - headers already sent by (output started at /some/file.php:12) in /some/file.php on line 23

The lines mentioned in the error messages contain header() and setcookie() calls.

What could be the reason for this? And how to fix it?

11 Answer