We have a list that was created in one SharePoint 2013 Web Application that utilizes a Nintex Form and also a Nintex Workflow. We attempted to move the list to our Development environment so that we could make changes to the form/workflow.
1. We saved the list as a template.
2. We used that template to create a new list in the Development environment.
3. We opened the Nintex form and published it.
Here is where the problem occurs. When I open the form in the Form Designer and click Preview, I get the error that says there has been an unexpected error. I can publish the form without error, but when I attempt to create a new list item, I get the same "Unexpected error."
I have been searching for guidance on moving lists that use Nintex forms and I can't find any possible reason I get an error. The list itself does not contain any lookups and only one People field. All the rest are text, numbers and currency.
I have not attempted to move the workflow to the new list because the form won't work.
I did the same many times from PROD to DEV and vice versa, I never had issues and it should work.
Could you please verify your Nintex Forms versions on PROD and DEV, if there is a huge difference in versions, it could be a problem, just a guess.
Another thing you can try is, save a copy of Nintex Form of your list in DEV and delete it. Create a new form and see if the new form opens without any issue. If it opens, then there should be some issue in the Form that came from PROD. This is to just to isolate the problem.