Sender Marketplace Adapter - 500 Internal Server Error

Hi,

My requirement is Marketplace -> PI 7.3 -> ECC in a B2B scenario. My customer is sending xCBL Orders from marketplace. For this I have configured Sender Marketplace adapter in PI (using HTTPS).

I have asked the customer to send data to the url https://<host>:<port>/MessagingSystem/receive/MPA/MML 

and have provided him with the logon data. 

But when the customer is trying to send the data, he is getting 500 - Internal Server Error response. Could you please let me know whats the issue? Its really urgent, so urgent help is appreciated.

But when I opened the URL on my browser I get following response:

<StatusInfo>

<StatusMessage>MessagingServlet is active.</StatusMessage>

<Version>Messaging System 7.1</Version>

<Usage>

http://[host]:[port]/MessagingSystem/receive/[connection]/[protocol]

</Usage>

<RequestURL>

https://[host]:[port]/MessagingSystem/receive/MPA/MML

</RequestURL>

<Connection>

<Name>MPA</Name>

<Status>started</Status>

<Listener>registered</Listener>

</Connection>

<Protocol>

<Name>MML</Name>

<Status>EventHandler registered</Status>

</Protocol>

</StatusInfo>

Thanks,

Regards,

Mateen.