What is the version of SharePoint you are currently using?
If you are on SharePoint Server, please check as following to narrow down this issue:
- The error suggests that your permission may not be sufficient for the GetUserCollectionFromGroup method to enumerate SharePoint groups and users, and so the method fails, referring to this document: "Access Denied" error (Event ID 5566) when you open a form in the browser. Make sure the account you use to publish the form is a member of the Farm Administrators group via Central Administration > Security > Manage the farm administrators group.
Or use the workaround mentioned in the document to change the permissions of the SharePoint groups that the form enumerates. - Disable Loop Back Check on all SharePoint servers.
- Referring to another article here, this error is expected when making a Web service call in SharePoint configured with Claims Based Authentication.
You can follow the instructions and see how to avoid this error.
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