How to call XML-RPC from WSO2 API Manager?

Invoking XML-RPC method from Postman Works good but when i deploy this API in the WSO2 API Gateway it give me an "error decoding RPC".

Example of XML payload.

<?xml version="1.0"?>
<methodCall>
   <methodName>vpop.emailinfo</methodName>
      <params>
         <param>
            <value><string>oussama@test.com</string></value>
         </param>
      </params>
</methodCall>

Example of error response :

<string>error decoding RPC.

no element found at line 1, column 0, byte -1 at /usr/lib/perl5/vendor_perl/5.10.0/x86_64-linux-thread-multi/XML/Parser.pm line 187.
</string>

I have to add Content-Length to the header with the value in Postman to works.but when i add this to API Manager still same error.

As mentioned by Athiththan, I tried adding the disable-chunking mediation policy with the respective API and it works .