cannot modify header information

Warning: Cannot modify header information - headers already sent by (output started at /home/***/domains/***/public_html/wp-content/themes/****/functions.php:1) in /home/****/domains/****/public_html/wp-includes/pluggable.php on line 1167 سلام خطای بالا رو با هر راه حلی که در اینترنت و فروم...