Problems for deleting user

Hi everybody,

When I try to delete a user with osuser, or when I want to delete a member
of a group I always get:

HTTP ERROR: 500 Credentials provider failed to remove user

RequestURI=/Nosica_demo0-Workflow/version_0/manager/user

I get an immutable Exception

I can create a user, but not delete him !
Could anyone help me ??
Thanks

Seb




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