BizTalk WSE 2.0 Adapter error in Send Port

Hello,

In our BizTalk 2006 SIT environment, we are getting an error while trying to send message using WSE 2.0 Adapter.

Error: : MustUnderstand headers:[{http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd}Security] are not understood

Backgroud: We have deployed our code in the SIT environment. We installed the certification in the certificate store required for the external WS. We copied the policy file (PolicyCache.xml) from UAT (location: D:\Program Files\Microsoft BizTalk Server Adapter for WSE 2.0\Policy). We did not create separately for SIT. Now when we trying to send message to the external WS using WSE adapter getting the above error.

In the BizTalk WSE Send port, WSE Transport property (URL: https://abcd10.abcd.com:8006/XXX/XYZ). We have a virtual site hosted in the local for theXYZ.WSDL file.