This error means the JSON entered has formatting mistakes, so the system can’t read it correctly.
If a user tries to save a form with any blank pages or if there are no items attached from the toolbox, you will get the error message 'The JSON you have entered for this form is invalid. Please see below the form editor for specific issues.'
If you have this error shown, please raise a new case online and reference the title of this article, attaching a copy of the data from the form editor.