org.xml.sax.SAXException: Bad envelope tag:  html

Hi,
  I am getting following exception in our application.
What would be reason? How to solve this?
Only change we did was we changed server url of actuate report.
It is giving exception when it is going through login flow.

 AxisFault
 faultCode: {http://xml.apache.org/axis/}Server.userException
 faultString: org.xml.sax.SAXException: Bad envelope tag:  html
 faultActor: null
 faultDetail:
      stackTrace: org.xml.sax.SAXException: Bad envelope tag:  html
      at org.apache.axis.message.EnvelopeBuilder.startElement(EnvelopeBuilder.java:106)
      at org.apache.axis.encoding.DeserializationContextImpl.startElement(DeserializationContextImpl.java:870)
      at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown Source)
      at org.apache.xerces.impl.XMLNamespaceBinder.handleStartElement(Unknown Source)
      at org.apache.xerces.impl.XMLNamespaceBinder.startElement(Unknown Source)
      at org.apache.xerces.impl.dtd.XMLDTDValidator.startElement(Unknown Source)
      at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source)
      at org.apache.xerces.impl.XMLDocumentScannerImpl$ContentDispatcher.scanRootElementHook(Unknown Source)
      at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
      at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
      at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
      at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
      at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
      at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
      at javax.xml.parsers.SAXParser.parse(Unknown Source)
      at org.apache.axis.encoding.DeserializationContextImpl.parse(DeserializationContextImpl.java:213)
      at org.apache.axis.SOAPPart.getAsSOAPEnvelope(SOAPPart.java:457)
      at org.apache.axis.Message.getSOAPEnvelope(Message.java:362)
      at org.apache.axis.client.Call.invokeEngine(Call.java:2046)
      at org.apache.axis.client.Call.invoke(Call.java:2016)
      at org.apache.axis.client.Call.invoke(Call.java:1786)
      at org.apache.axis.client.Call.invoke(Call.java:1711)
      at org.apache.axis.client.Call.invoke(Call.java:1251)Start Free Trial