Error "Unable to find a Routing corresponding to the incoming request messag (20, 505)" while trying

1) While trying to view the WSDL in a browser for any of the AAWS (Admission Application Web Services), getting error "XML" as posted below,2) Earlier, I was able to see the WSDL file without any issues,
3) All IB settings are correct and all nodes are pingable,
4) Now sure what happeded?

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<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">

<SOAP-ENV:Body>

<SOAP-ENV:Fault>

<faultcode>SOAP-ENV:Server</faultcode>

<faultstring>null</faultstring>

<detail>

<IBResponse xmlns="" type="error">

<DefaultTitle>Integration Broker Response</DefaultTitle>

<StatusCode>20</StatusCode>

<MessageID>505</MessageID>

<DefaultMessage>

<![CDATA[

Unable to find a Routing corresponding to the incoming request message.

]]>

</DefaultMessage>

<MessageParameters/>