Sometimes when you start importing a layout from another website (or the same site as well), you see an error message like the below.
Reason: Each exported layout is assigned one of these 3 contexts to it:
et_builder_layouts - For a layout exported from Divi > Divi Library or Divi Cloud.
et_builder - For a layout that is exported from an individual page/post.
et_theme_builder - For templates exported from Theme Builder.
Layouts exported from Divi > Library or from Divi Cloud can only be imported in the Library page. The ones exported from an individual post or page can only be imported in the same context (on a page/post or any other custom post type).
If you see this error while importing the layout on an individual page, you can go to Divi > Divi Library, import the layout there first and then import the newly imported layout from Divi Library or Divi Cloud on your page.
If you see the error while importing the layout in Divi Library or on Divi Cloud, you can simply make a new page and import the layout there instead of importing to the library, if you want to save it for future use, you can save it to the Divi Library from your newly created page.
If you can't import the .json file on either a page/post or the Divi Library, then most likely it's a file exported from Theme Builder and it should be imported in Divi > Theme Builder > Portability System.
P.S. Divi Cloud note: If you've purchased a layout(or more) and you're trying to upload them on Divi Cloud but you receive this error, that means the .json file is an individual layout that needs to be imported on an individual page first.
Once you upload it on an individual page, you will be able to save it to the Divi Cloud directly from the Visual Builder: