Hello Tomasz,

Thanks for reaching out to us. I checked your site locally, and it works as expected. The issue seems to be with your hosting provider, as it is blocking requests from SP Page Builder when trying to save data.

I recommend contacting your hosting provider and asking them to temporarily disable ModSecurity, WAF rules, or any other security filters that might be causing this issue.

Let me know if you need further assistance!

Best regards,

as I wrote at the very beginning: ModSecurity is disabled in the file: .htaccess all elements in joomla and other plugins can be saved