I am getting this error when adding a look up list to my Nintex FOrm, any idea why?
Go to the list/library settings page, The URL in the browser from that screen will have the guid.
Was this list copied or from a template? If you hit refresh, does the list still come up in the drop down?
From the screen print, it shows list does not exit. so please recheck again whether the source list exist or not. if exist then use the source List GUID instead of List name.
How do I get list GUID?
Sent from my iPhone
You can get links to all non-hidden lists' settings pages (that include GUIDs) from <yoursite>/_layouts/mcontent.aspx (Site settings -> Site lists and libraries)
Retrieving data ...