SSRS data services Sharepoint 2013 xml - sharepoint

Question

in SSRS 2016 I write the following XML data Source:
https://<site>/_vti_bin/usergroup.asmx
and afterwards the following DataSet:
<Query>
<SoapAction>http://schemas.microsoft.com/sharepoint/soap/directory/GetGroupCollectionFromUser
</SoapAction>
<Method Namespace="http://schemas.microsoft.com/sharepoint/soap/directory"
Name="GetGroupCollectionFromUser">
<Parameters>
<Parameter Name="userLoginName">
<DefaultValue>user</DefaultValue>
</Parameter>
</Parameters>
</Method>
<ElementPath IgnoreNamespaces="true">*</ElementPath>
</Query>
being user a dataSetParameter=User!UserID
launching the query in the query designer I get the following error. Help is really appreciated:
===================================
An error occurred while executing the query.
Failed to execute web request for the specified URL.
Soap Fault:
Exception of type 'Microsoft.SharePoint.SoapServer.SoapServerException' was thrown. (Microsoft SQL Server Report Builder)
===================================
Failed to execute web request for the specified URL.
The remote server returned an error: (500) Internal Server Error.
<?xml version="1.0" encoding="utf-8"?><soap:Envelope
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<soap:Fault>
<faultcode>soap:Server</faultcode>
<faultstring>Exception of type
'Microsoft.SharePoint.SoapServer.SoapServerException' was
thrown.
</faultstring><detail><errorstring
xmlns="http://schemas.microsoft.com/sharepoint/soap/">The parameter
loginName cannot be empty or bigger than 251 characters.</errorstring>
<errorcode
xmlns="http://schemas.microsoft.com/sharepoint/soap/">0x80131600</errorcode>
</detail></soap:Fault></soap:Body>
</soap:Envelope>