To allow application access to user profiles
On the upper right of the Nintex Forms for Office 365 page, click Nintex Forms Admin and then select Allow Application Access to User Profiles.
Note: If you don't see the Nintex Forms Admin option, your user account may not be a member of the Owners group for the site. To add your account to the Owners group, go to the Site Contents page for the site, click Site Permissions, select Advanced permissions settings, find the Owners group (the group name starts with the site name), and use SharePoint options to add your account.
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