Login Error Cokies

Someone out there can please help me? When I try to login I get always the Cookies error. Because of this I activatad the debug modus an now I get this:

Warning: Cannot modify header information – headers already sent by (output started at /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-config.php:1) in /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-login.php on line 390 Warning: Cannot modify header information – headers already sent by (output started at /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-config.php:1) in /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-login.php on line 403 Warning: Cannot modify header information – headers already sent by (output started at /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-config.php:1) in /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-includes/pluggable.php on line 898 Warning: Cannot modify header information – headers already sent by (output started at /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-config.php:1) in /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-includes/pluggable.php on line 899 Warning: Cannot modify header information – headers already sent by (output started at /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-config.php:1) in /mnt/webb/e3/79/53909279/htdocs/WordPress_01/wp-includes/pluggable.php on line 900

WHAT can I do? Thank you in advance for any help.