Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, non-static method OWA_Block::register_widget_sidebar() cannot be called statically in /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/class-wp-hook.php:324 Stack trace: #0 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters('', Array) #1 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #2 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/widgets.php(1862): do_action('widgets_init') #3 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/class-wp-hook.php(324): wp_widgets_init('') #4 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array) #5 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #6 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-settings.php(695): do_action('init') #7 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-config.php(94): require_once('/data01/virt100...') #8 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-load.php(50): require_once('/data01/virt100...') #9 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-blog-header.php(13): require_once('/data01/virt100...') #10 /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/index.php(17): require('/data01/virt100...') #11 {main} thrown in /data01/virt100087/domeenid/www.ahmadiyya.ee/htdocs/wp-includes/class-wp-hook.php on line 324