wp_mail not working with to address

I am getting the email address of the author of a post with

$postauthoremail = the_author_meta('user_email');

This does contain the correct email address.

If I feed that into wp_mail:

wp_mail($postauthoremail, $subject, $message);

This does not work.

If I hard code the email:

wp_mail('myemail@domain.com', $subject, $message);

This does work.

I have tried adding quotation marks to $postauthoremail, converting it to string, etc and does not help.

Any help is appreciated.