DevOps, CI/CD and Automation

I have a problem with the notion of Namespaces and path.

i try this code

variable   xml_response varchar2(4000);

BEGIN

:xml_response :=

'<?xml version="1.0" encoding="UTF-8"?>
<S:Envelope xmlns:S="http://schemas.xmlsoap.org/soap/envelope/">
   <S:Body>
      <GenerateLabelResponse xmlns="https://www.mypostbusiness.ch/wsbc/barcode/v2_2/types">
         <Envelope>
            <LabelDefinition>
               <ImageFileType>PDF</ImageFileType>
            </LabelDefinition>
            <Data>
               <Provider>
                  <Sending>
                     <Item>
                        <ItemID>12346</ItemID>
                        <IdentCode>993314781300000277</IdentCode>
                        <Image>Base64 encoded data</Image>
                     </Item>
                  </Sending>
               </Provider>
            </Data>
         </Envelope>
      </GenerateLabelResponse>
   </S:Body>
</S:Envelope>';

END;
/

SELECT x1.*
FROM XMLTable(
       XMLNamespaces(default 'https://www.mypostbusiness.ch/wsbc/barcode/v2_2/types')
     , '/GenerateLabelResponse/Envelope/Data/Provider/Sending/Item'
       passing xmltype(:xml_response)
       columns
         ItemID varchar2(30) path '/ItemID',
         IdentCode varchar2(30) path '/IdentCode'
     ) x1
;

and have a return of no rows.

i have think that the namespaces determine the root of the path and i have only to follow the path since i have the right column.

what is wrong?