Hi @savvaskef
Are you trying to ‘edit’ an existing post?
Or are you trying to create a form to create a new post?
Usually, when you need to define the field_groups arg, you are creating a new post. If this is the case, please remove the ‘post_id’ parameter.
Also, you must better describe what you are seeing. When you say ‘blank’, do you mean the entire screen is white? Or just that the form is not displaying?
If the screen is completely white, please turn on DEBUG_MODE in your wp-config.php file to show PHP errors. It is possible that you have a syntax error.
Thanks
E
