When opening an item with a Nintex Form that has either a Lookup control, or a People Group control, the following error might occur:
Something went wrong.
Grant the user permissions to the list that the lookup column on the form is attempting to pull data from.
- Navigate to Site Settings > People and Groups.
- Select the associated group being referenced in the People/Group control.
- Select Settings > Group Settings.
- Update 'Who can view the membership of the group?' from 'Group Members' to 'Everyone'.