mule : Until successful doesn't accept the data weave transform - mule

Question

I have a scenario where in I need to call the service until the http status of the webservice call is 200.
The subflow(SearchSubFlow) works fine when it is not in Until Successful but when it is inside Until Sucessful it falls over with the below error at Byte Array to String in SearchSubFlow.
org.mule.api.transformer.TransformerMessagingException: null (java.lang.NullPointerException). Message payload is of type: WeaveMessageProcessor$WeaveOutputHandler.
<flow name="CheckFlow">
<http:listener config-ref="HTTP_Internal_Listener" path="${CONNECTION_URI}" doc:name="HTTP"/>
<cxf:proxy-service payload="envelope" doc:name="CXF" namespace="http://abc/RetrieveService" service="RetrieveService" soapVersion="1.2" wsdlLocation="${WSDL_RETRIEVE}"/>
<mulexml:dom-to-xml-transformer doc:name="DOM to XML"/>
<set-variable variableName="Ref" value="#[xpath3('//*:CheckRequest/*:Ref')]" doc:name="Get External Ref Number"/>
<until-successful objectStore-ref="objectStore" maxRetries="${RESEND_COUNTER}" millisBetweenRetries="${RESEND_INTERVAL}" doc:name="Retry to check policy status" >
<flow-ref name="SearchSubFlow" doc:name="SearchSubFlow"/>
</until-successful>
</flow>
<sub-flow name="SearchSubFlow">
<dw:transform-message doc:name="PolicySearchWS Request">
<dw:set-payload><![CDATA[%dw 1.0
%output application/xml
%namespace soapenv http://schemas.xmlsoap.org/soap/envelope/
---
{
soapenv#Envelope: {
soapenv#Header: {
InsureJHeader:{
role: "${HEADER_ROLE}"
}
},
soapenv#Body: {
arguments:{
externalQuoteReference: flowVars.Ref
}
}
}
}]]></dw:set-payload>
</dw:transform-message>
<byte-array-to-string-transformer doc:name="Byte Array to String"/>
<message-properties-transformer scope="invocation" doc:name="Set Service Endpoint">
<add-message-property key="serviceEndPoint" value="${APP_SYSTEM}/${SELECT_SERVICE_BASE_URL}/${.CREATE.ADDRESS}"/>
</message-properties-transformer>
<message-properties-transformer doc:name="Set SOAP Action">
<add-message-property key="SOAPAction" value="${CREATE.SOAPACTION}"/>
</message-properties-transformer>
<cxf:proxy-client payload="envelope" doc:name="Proxy"/>
<http:request config-ref="HTTP_Select_Request" path="#[serviceEndPoint]" method="POST" doc:name="Call Search WS">
<http:success-status-code-validator values="200,500"/>
</http:request>
<mulexml:dom-to-xml-transformer doc:name="DOM to XML"/>
<message-properties-transformer scope="invocation" doc:name="Message Properties">
<add-message-property key="PolicySearchErrorMessage" value="#[xpath3('//*:Fault/*:ProcessingFault/*:message')]"/>
<add-message-property key="httpStatus" value="#[message.inboundProperties.'http.status']"/>
</message-properties-transformer>
</sub-flow>
Highly appreciate your help!

Answer 1

Not referencing to the objectstore as below resolved the issue
<until-successful maxRetries=5 doc:name="Retry to check status" >
<flow-ref name="SearchSubFlow" doc:name="SearchSubFlow"/>
</until-successful>

Answer 2

use <mulexml:dom-to-xml-transformer doc:name="DOM to XML"/> instead of <byte-array-to-string-transformer doc:name="Byte Array to String"/>
Hope this helps.