Have you ever used Google's 'Structured Data Testing Tool' and received the error 'A value for the item field is required.' when validating your breadcrumblist.
The error message is vague and could probably leave you scratching your head trying to work out the problem.
If that's you, then try the following which should solve the error.
It seems that using the testing tool, Google expects a valid URL, the problem is if you are working on the site locally and dynamically create your URL's, or you are using Local IIS and have created your domain name like the following https://website.local/ then Google will complain that the URL is not valid, but instead of actually saying that, you get the error displayed.
The easiest way to fix the problem is to just change the domain to a valid URL, .com/co.uk etc, or just add a '/' for the website name and this will fix the problem.