Custom post type - Errors

Question

I am getting these errors:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, no array or string given in C:...\class-wp-hook.php on line 298

Warning: Cannot modify header information - headers already sent by (output started at C:...\www\customTheme\wp-login.php on line 394 <- and line 407

After I add a custom post type and call:

add_action('after_setup_theme', PostTypeCreate_Works());

Because of these warnings I am getting this error on the login: Cookies are blocked due to unexpected output.

Anyone know why this is happening?

Answer 1

read https://developer.wordpress.org/reference/functions/add_action/

then use:

add_action('after_setup_theme', 'PostTypeCreate_Works');