php - SOAP 1.1 Request Fatal Error Uncaught SoapFault exception: [soapenv:Server] -

my request following:

 $client = new soapclient("http://xxx.de:8080xxxwebservice?wsdl", array("trace" => 1, "soap_version" => soap_1_1));  $result = $client->__soapcall("calcmietpreis", array('calabholdatum' => "2015-08-08 11:14:15", 'calrueckgabedatum' => "2015-08-09 11:14:15")); 

and got following error message:

fatal error: uncaught soapfault exception: [soapenv:server] exception occurred while trying invoke service method calcmietpreis in /srv/www/htd... 

i not know ... searched everywhere.

i installed php extension soap , _getfunctions give me existing functions. think connection exists.

looks wsdl isnt supposed use php instead java client.