When encountering the "This form contains a hidden field that does not have a valid default value configured" error message on the customer portal, JSM doesn't make it clear which field/value is causing problems in submitting the issue creation form which can cause confusion and lead to a needle in the haystack search for the configuration issue.

By inspecting the server response logged in the Developer Panel > Network tab (as explained in this article), we can see exactly which field/value is causing the problems, so by making this information available in the UI we can shorten the troubleshooting process and make the solution easier for admins.