Problem setting file system access rule

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C#

Hi.
In my app on local network, any user should create a directory on shared folder using this code. test1 is the name of one of the user's folder for example.

DirectoryInfo di = new DirectoryInfo(@"\\Server\Test\test1"); DirectorySecurity ds=new DirectorySecurity(); ds.SetAccessRule(new FileSystemAccessRule(Enviroment.Username,FileSystemRights.FullControl, AccessControlType.Deny));  di.Create(ds);

Now when the admin in domain wants to read every directory from any user this error ocurred:

Attempted to perform an unauthorized operation.
The code that the admin runs is:

DirectoryInfo di = new DirectoryInfo(@"\\Server\Test\test1"); DirectorySecurity ds=new DirectorySecurity(); ds.SetAccessRule(new FileSystemAccessRule(Enviroment.Username, FileSystemRights.FullControl, AccessControlType.Allow));  di.SetAccessControl(ds); 

Where is my mistake?
Thanks in advance.