Errores al acceder a la administración de WordPress

Hola foreros, felices fiestas antes que nada. Tengo un problema con una nueva instalacion limpia de wordpress, en la pagina principal no da ningun problema y funciona perfectamente, pero si accedo a la administracion me arroja estos errores tras loguearme:

Warning: Cannot modify header information - headers already sent by (output started at /home/fmntprsv/public_html/wp-config.php:1) in /home/fmntprsv/public_html/wp-login.php on line 349

Warning: Cannot modify header information - headers already sent by (output started at /home/fmntprsv/public_html/wp-config.php:1) in /home/fmntprsv/public_html/wp-login.php on line 361

Warning: Cannot modify header information - headers already sent by (output started at /home/fmntprsv/public_html/wp-config.php:1) in /home/fmntprsv/public_html/wp-includes/pluggable.php on line 669

Warning: Cannot modify header information - headers already sent by (output started at /home/fmntprsv/public_html/wp-config.php:1) in /home/fmntprsv/public_html/wp-includes/pluggable.php on line 670

Warning: Cannot modify header information - headers already sent by (output started at /home/fmntprsv/public_html/wp-config.php:1) in /home/fmntprsv/public_html/wp-includes/pluggable.php on line 671

Warning: Cannot modify header information - headers already sent by (output started at /home/fmntprsv/public_html/wp-config.php:1) in /home/fmntprsv/public_html/wp-includes/pluggable.php on line 866

alguna ayuda? gracias anticipadas

¿Utilizas algún plugin de seguridad para loguearte?

mira si hay espacios delante del <?php o detras del ?> en /home/fmntprsv/public_html/wp-config.php

Wordpress Error: Warning: Cannot modify header information

He quitado un espacio que habia al final, ahora me sale este error:

¿
Warning: Cannot modify header information - headers already sent by (output started at /home/fmntprsv/public_html/wp-config.php:1) in /home/fmntprsv/public_html/wp-includes/pluggable.php on line 866

en la linea 866 de ese archivo hay:

header("Location: $location", true, $status);

Alguna idea? salu2