Some email clients do not work well with angled brackets around links - which is the default format. This snippet will add another link to the password reset email without the angled brackets.

Add link to WP password reset email - sans angled brackets

function fix_password_reset_link($message, $key, $user_login, $user_data) {
	$message .= "\r\nLink not working? Copy and paste the following into your browser address bar:\r\n\r\n";
	$message .= network_site_url("wp-login.php?action=rp&key=$key&login=" . rawurlencode($user_login), 'login');

	return $message;
}
add_filter( 'retrieve_password_message', 'fix_password_reset_link', 10, 4);