When trying to open task forms using 'Edit Task Form' > 'Edit with Nintex Forms' the form designer doesn't open. This issue is affecting all tasks on all workflows within one of our site collections. The forms were previously working on this site collection. We haven't made any changes to Nintex workflow on this site collection other than publishing updated versions of a few workflows recently.
This has also caused some of the existing tasks which are using Nintex forms to no longer be accessible.
The SharePoint logs show the following error: "Failed to retrieve form from workflow. Error: Cannot find the task form. Please check the action's form in the Workflow Designer."
I've done a bit of research on this and see some suggestions to disable and re-enable the 'Nintex workflow forms' feature on the site collection. I would prefer not to do this though if we will lose workflow task forms and need to recreate/re-import them. Has anyone else experienced this issue?
I had the same issue in our QAS and PRD environments (version 2013). I tested the disabling and re-enabling of the site collection feature: “Nintex Forms for Nintex Workflow” in QAS and doing this did not delete any forms, all forms and task forms were still there. I did the same in our PRD enviroment and had the same success.
In the event that this may assist someone else, I had the same problem on my SharePoint 2016 on-Prem environment and disabling and re-enabling Nintex forms for Nintex Workflow resolved the issue without causing any problems or loss of data.