I set up a network of websites with multisite. One of these is the main blog.
I want to show the categories and items common to all blogs.
I used the function switch_to_blog (1) where 1 is the ID of the site "father" to populate a select with category values.
Obviously selecting a category, show me the 404 page as the blog "child" category that does not really exist.
Should I put a condition to understand when making the switch between blogs, but I do not know where to insert it.
Who can help me?