Wp-admin / Login.php crashed

Hello SiteOrigin

I am using your theme ‘Prospect’ and now i can’t login my wordpress: http://bruunoggejl.dk

Wp-admin gives me this error:

Warning: Cannot modify header information – headers already sent by (output started at /var/www/bruunoggejl.dk/public_html/wp-content/themes/origin/functions.php:347) in /var/www/bruunoggejl.dk/public_html/wp-includes/pluggable.php on line 1207

Wp-login gives me this error:

Warning: Cannot modify header information – headers already sent by (output started at /var/www/bruunoggejl.dk/public_html/wp-content/themes/origin/functions.php:347) in /var/www/bruunoggejl.dk/public_html/wp-login.php on line 431</p>
<p>Warning: Cannot modify header information – headers already sent by (output started at /var/www/bruunoggejl.dk/public_html/wp-content/themes/origin/functions.php:347) in /var/www/bruunoggejl.dk/public_html/wp-login.php on line 444</p>
<p>Warning: Cannot modify header information – headers already sent by (output started at /var/www/bruunoggejl.dk/public_html/wp-content/themes/origin/functions.php:347) in /var/www/bruunoggejl.dk/public_html/wp-includes/pluggable.php on line 935</p>
<p>Warning: Cannot modify header information – headers already sent by (output started at /var/www/bruunoggejl.dk/public_html/wp-content/themes/origin/functions.php:347) in /var/www/bruunoggejl.dk/public_html/wp-includes/pluggable.php on line 936</p>
<p>Warning: Cannot modify header information – headers already sent by (output started at /var/www/bruunoggejl.dk/public_html/wp-content/themes/origin/functions.php:347) in /var/www/bruunoggejl.dk/public_html/wp-includes/pluggable.php on line 937</p>
<p>Warning: Cannot modify header information – headers already sent by (output started at /var/www/bruunoggejl.dk/public_html/wp-content/themes/origin/functions.php:347) in /var/www/bruunoggejl.dk/public_html/wp-includes/pluggable.php on line 1207

I have tried deactivating all my plugins through FTP, but have come to realize that it has something to do with a WordPress update, and your theme!

Can you help me out? This is a really big error, that will come to cost me a lot of money.

URL: http://bruunoggejl.dk