Child Theme won’t work

Hello everyone,

i’m trying to get my child theme running on my main wp installation. at the theme selection page it gets displayed withut error, but once activated i am stuck with a blank white page and nothing helps but upload a backup db -_-‘ the curious thing is, the same child is working wonderful with another installation i duplicated from my main page with the duplicator plugin…

so, is there anything wrong with my code, or can anyone suggest something i can try?

my functions.php

function siteorigin_north_child_styles() {
wp_deregister_style( 'siteorigin-north-style');
wp_register_style('siteorigin-north-style', get_template_directory_uri(). '/style.css');
wp_enqueue_style('siteorigin-north-style', get_template_directory_uri(). '/style.css');
wp_enqueue_style( 'childtheme-style', get_stylesheet_directory_uri().'/style.css', array('siteorigin-north-style') );
}
add_action( 'wp_enqueue_scripts', 'siteorigin_north_child_styles' );

and my style.css (just not with the real names^^)

/*
 Theme Name:    myTheme
 Theme URI:     http://myTheme.de/theme/myTheme
 Description:   Basierend auf SiteOrigins North Theme, eine Anpassung für die Firma myTheme
 Author:        McLexx
 Author URI:    http://myTheme.de
 Template:      siteorigin-north
Text Domain: siteorigin-north
 Version:       1.0.0
 License:       GNU General Public License v2 or later
 License URI:   http://www.gnu.org/licenses/gpl-2.0.html
Tags: one-column, two-columns, left-sidebar, right-sidebar, custom-background, custom-colors, custom-menu, custom-logo, featured-images, footer-widgets, full-width-template, post-formats, rtl-language-support, sticky-post, theme-options, threaded-comments, translation-ready, blog, e-commerce
*/