@CMB-Abovet ,
Until it's not possible to check it from the form itself,
I would recommend to check from the workflow for an existing item with the same field value first, and then, if only it does not exist, create the item. Avoid the error happening as a best practice.
You can also create your own Xtensions to create the item and get errors responses. But It's not a handling exceptions best practice. Exceptions should not be used for logic.
Keep in mind that if you use Nintex Forms for Office 365, it's managed. You stay on the form and are prompted with a message as shown below :
The question maybe, should I use Nintex for Office 365 for that specific reason ? This could be changed faster.
My2cents
^^
Thank you Cecilia for your answer. I will go ahead and apply your first suggestion!
This form needs to be available for the public , so I believe i cannot use Nintex Forms for Office 365. Isn't that correct?
Thank you,
AB
@CMB-Abovet,
That's correct. Public forms is only possible with Nintex Workflow Cloud.
With Office 365, you can authorize external users, but the form SharePoint or Nintex is still not anonymous and you are authenticated.
^^