Unexpected error after update adamos theme to ver 2.0

hi there…please help me…!
i have this error after auto update adamos theme

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘adamos_custom_header_setup’ not found or invalid function name in /home/xxxxxxxx/public_html/wp-includes/plugin.php on line 505

Warning: Cannot modify header information – headers already sent by (output started at /home/xxxxxxxx/public_html/wp-includes/plugin.php:505) in /home/beew9784/public_html/wp-includes/pluggable.php on line 1179

Please help me…because i can’t login into admin dashboard.

thankyou all