Empower API 400 bad request, how to resolve this?

I am trying to make SOAP request to the API at https://management.empowersoftware.co.nz/api/EmpowerAPI.asmx But, when I try to get data from the API, I get the following error: "400 Bad request" Below is the post data:

    <?xml version="1.0" encoding="EBCDIC-CP-US" ?>
<soapenv:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:web="http://schemas.xmlsoap.org/soap/envelope/">
<soapenv:Header xmlns:soapenv="http://www.w3.org/2003/05/soap-header">
      <web:AuthenticationCredential>
         <web:UserName>********</web:UserName>
         <web:Password>********</web:Password>
      </web:AuthenticationCredential>
   </soapenv:Header>
    <soapenv:Body>
      <web:GetChecklistDetails>
          <web:StartDate>2022-08-20 12:00:00</web:StartDate>
         <web:EndDate>2022-08-28 12:00:00</web:EndDate>
      </web:GetChecklistDetails>
</soapenv:Body>
   </soapenv:Envelope>

Can any one help me to resolve this? Thanks in Advance.