RafalManka

hello, the easiest solution for this problem would be to:
1. open wp-content/plugins/clean-login/clean-login.php
2. scroll to line 302 (tle last else statement of “// REGISTER a new user” section before wp_safe_redirect( $url );).
3. paste this code:

$creds = array();
$creds['user_login'] = $_POST['username'];
$creds['user_password'] = $_POST['pass1'];

if($creds['user_login']!=''&&$creds['user_password']!=''){
	$creds['remember'] = true;

	wp_signon( $creds, false );
	// this will redirect to the main page. if you want this
	// to be a specific page you have to replace it with something
	// like '/?page_id=123'
	$redirect_to_link = '/';
	wp_safe_redirect( $redirect_to_link );
	return;
}

4. test and enjoy.