Impersonation through C# is not working - sending wrong CallingID

Question

Hello,
I need to modify the UserQuery entity, but per securities I can't update this unless it's updated as each individual user.  So I've written a piece to update it using Impersonation by setting the CallerID.  Below is a snippet of the code:
using (OrganizationServiceProxy proxy = new OrganizationServiceProxy(SvcMgt, Creds))
Guid OwnerID = new Guid("0c5b54bb-f2ab-e411-94aa-005056843a89");
proxy.CallerId = OwnerID;
Guid UserQueryId = new Guid((row["UserQueryId"].ToString()));
ColumnSet attributes = new ColumnSet(new string[] { "fetchxml"});
Entity userquery = new Entity("userquery");
userquery = proxy.Retrieve(userquery.LogicalName, UserQueryId, attributes);
userquery["fetchxml"] = row["FixedFetchXML"].ToString();
proxy.Update(userquery);
When I run this I get the error below:
System.ServiceModel.FaultException`1[Microsoft.Xrm.Sdk.OrganizationServiceFault]: 
SecLib::AccessCheckEx failed. Returned hr = -2147187962, 
ObjectID: 428e02bb-acb3-e411-94aa-005056843a89, 
OwnerId: 0c5b54bb-f2ab-e411-94aa-005056843a89,  
OwnerIdType: 8 and 
CallingUser: e0d62cbb-86d6-e411-94aa-005056843a89. 
ObjectTypeCode: 4230, 
objectBusinessUnitId: 45072abb-5187-e211-86aa-005056b07049, 
AccessRights: Read
Access  (Fault Detail is equal to Microsoft.Xrm.Sdk.OrganizationServiceFault).
The CallingUser is me, but I assumed this would be the user I'm trying to impersonate given I've set that GUID as the CallerID.  What am I missing?
Thanks in advance for any suggestions.

Answer 1

Thanks for the options.  What I'm seeing now is my Impersonation code is working when I set the CallerId, but it's not working congruently across all users.  For example I have two users, and I can run the following for one user and it creates
the Contact under that user, but if I change the CallerId to another User's GUID it creates the Contact under me and not that second user:
using (OrganizationServiceProxy proxy = new OrganizationServiceProxy(SvcMgt, Creds))
proxy.CallerId = new Guid("BBC683AA-3E8B-E211-98BB-005056B07049");
Guid NewContact;
Entity contact = new Entity("contact");
contact["firstname"] = "Test2";
contact["lastname"] = "Test2";
NewContact = proxy.Create(contact);
System.Console.WriteLine(NewContact.ToString());
At this point I believe my code is valid and working, because under the user that it works on the correct user is setup as the ModifyBy, CreateBy, etc  but I'm setup as the ModifiedOnBehalfBy and CreatedOnBehalfBy.  And I've even tested this with
updating the User Query entity, for some I can modify their Query successfully but for the same ones that won't allow me to setup a new Contact for them I can't update the User Query entity as them either.
So my question now is why does Impersonation work on some users but not on others.  I've compared the profiles of users that it does and doesn't work on, but I can't find any difference.
Thanks --