No visible cross in the popup window on the phone

Please, use this css in your custom css, You can follow this guide: https://www.joomshaper.com/documentation/helix-framework/custom-code-css-js-meta

@media (max-width: 768px) {
    #sp-pagebuilder-popup-close-btn-95 {
        right: 15px;
        top: 15px;
    }
}

Thanks

Please, use this, instead of previous one.

@media (max-width: 768px) {
    #sp-pagebuilder-popup-close-btn-95 {
        right: 15px !important;
        top: 15px  !important;
    }
}

Thanks

You are welcome.