Runtime Exception

Hello, launching this call:
WS.verifyElementPropertyValue(response, ‘.//multiRef/esito’, ‘OK’)

I get the following error:
Caused by: java.lang.RuntimeException: Lo spazio di nomi per il prefisso ‘soapenv’ non è stato dichiarato.

My response is:

<?xml version="1.0" encoding="UTF-8"?>

<soapenv:Envelope xmlns:soapenv=“” xmlns:xsd=“” xmlns:xsi=“”>
<ns1:activateLineResponse soapenv:encodingStyle=“” xmlns:ns1=“”>


Do you have any suggestions?
I noticed that it is the same case reported here:

Thank you.