Importing the wsdl file in postman - web-services

Question

I am trying to access the client URL web service in postman. I used the import link to import the wsdl file client URL in postman and successfully generated the collection. However, upon testing the request, I am unable to retrieve the data from the client server. I am only getting an empty element in the response body. I followed some of the SOAP Web Service tutorial on youtube and it is still the same. The client provided me the valid username for me to test but still the same.
This is my request body:
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<zhi_sa_mgt xmlns="urn:mss:jfnllns:df">
<P_DATE>2022-10-22</P_DATE>
<P_NAME>
<item>HPOITY</item>
</P_NAME>
</zhi_sa_mgt>
</soap:Body>
</soap:Envelope>
And the response body:
<?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>
<zhi_sa_mgt xmlns="urn:mss:jfnllns:df">
<P_DATA/>
</zhi_sa_mgt>
</soap:Body>
</soap:Envelope>
I just wanted to ask, what could be the possible reason/s on why I am getting the empty tag <P_DATA>? This is my first SOAP web service task and I cannot figure out why I cant retrieve the data from the client server. Thank you in advance for your response.