Warning: Cannot modify header information

Hi Everyone,

I keep getting this error on some of my pages as well as on the wp-admin page so I can’t log in.

Warning: Cannot modify header information – headers already sent by (output started at /home/bcr23/symfony/web/wp-admin/index.php:1) in /home/bcr23/symfony/web/wp-includes/pluggable.php on line 897

I’ve tried deleting all the spaces before and after the <?php on the functions.php, pluggable.php, wp-config.php. I’ve also changed the names of all my plugins to see if that was the problem but still nothing.

Anyone that could help would be much appreciated!