Marta,
It has been Fixed now, Please check and confirm.
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2. Additionally, today I switched on the codeless slider at home page. It caused that we can’t see any subpage. Everywhere there is a blog page under each link. Could you please check it? It’s urgent.
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About #1:
Please Deactive all the plug-ins which you are not using, your website and wp-admin is in Polish Language and I am not so familiar with that.
So, Please Explain me Point #1 in Deep details via Screen Shot, Surely, I can Help you today.

Thanks,

Margo,
Blog page is use to show the Post, Please be More specific which part of the page change.

If you want to change posts and you can edit from wp-admin > post > Edit post

Thanks,

Same error here. Please help.

Fatal error: Uncaught Error: Class ‘CodelessTwitter’ not found in /home/dsignpro08/public_html/wp-includes/class-wp-widget-factory.php:61 Stack trace: #0 /home/dsignpro08/public_html/wp-includes/widgets.php(115): WP_Widget_Factory->register(‘CodelessTwitter’) #1 /home/dsignpro08/public_html/wp-content/plugins/codeless-framework/admin/register-widgets.php(7): register_widget(‘CodelessTwitter’) #2 /home/dsignpro08/public_html/wp-includes/class-wp-hook.php(287): codeless_register_widgets(”) #3 /home/dsignpro08/public_html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array) #4 /home/dsignpro08/public_html/wp-includes/plugin.php(478): WP_Hook->do_action(Array) #5 /home/dsignpro08/public_html/wp-settings.php(518): do_action(‘after_setup_the…’) #6 /home/dsignpro08/public_html/wp-config.php(106): require_once(‘/home/dsignpro0…’) #7 /home/dsignpro08/public_html/wp-load.php(37): require_once(‘/home/dsignpro0…’) #8 /home/dsignpro08/public_html/wp-blog-header.php(13): require_once(‘/home/dsignpro0…’) #9 / in /home/dsignpro08/public_html/wp-includes/class-wp-widget-factory.php on line 61

Hello,

Can you check out this PHP file instead: wp-content/themes/folie/template-parts/entry-content/

// Display excerpt if auto excerpts are enabled in the admin
if ( codeless_get_mod( 'blog_excerpt', true ) && ( ! is_single() || codeless_get_from_element('blog_from_element', false) ) ) :

    if( get_the_excerpt() == '' ){
        $content    = get_the_content();
        $content    = preg_replace("~(?:\[/?)[^/\]]+/?\]~s", '', $content);
        echo  wp_trim_words( $content, codeless_get_mod('blog_excerpt_length', 40), ' [...]' );
    }
    else
        the_excerpt();

replace with:

// Display excerpt if auto excerpts are enabled in the admin
if ( codeless_get_mod( 'blog_excerpt', true ) && ( ! is_single() || codeless_get_from_element('blog_from_element', false) ) ) :

    if( get_the_excerpt() == '' ){
        $content    = get_the_content();
        $content    = preg_replace("~(?:\[/?)[^/\]]+/?\]~s", '', $content);
        $content = '';
    }
    else
         $content = '';

Let us know.

Regards!