Hi Jomo - I'm getting exactly the same error.
In my workflow, I'm using a variable to choose between 2 email addresses, then I assign that email address to a task.
Did you ever find a solution to your issue?
Hi Jomo
The issue for me was that I was using AD to select the person who should be assigned the task. This person often wasn't registered as a Nintex Workflow Cloud user.
My solution (until we find a better one), is to replace the 'assign a task' step with an email containing a link to a new workflow. When the person is asked to log in to this second workflow, they're created as a Nintex Workflow Cloud User.
I pass any relevant data from the previous workflow over as querystring parameters, including the previous workflow's instance ID, so I can relate the data when I save it to the database.
Alan
The real solution to my issue was to set up a [User Directory Lookup] connection in [Settings].
This way NWC can authenticate assigned tasks to AD users, rather than requiring them to be listed within [Settings > User Management]. Usually NWC users were previously only registered on logging into a form, but this removes that requirement, meaning you can [Assign a Task] to anyone, whether they've previously logged into a NWC form or not.
Any luck with this issue, as I have seen this coming up today,
My approve is from a sharepoint list.
Please advise?