stateful failover not work with Weblogic Server Cluster

 Hi Experts,

I created a Weblgoic server(10.3.6) cluster on one machine(on linux VM) with 3 peoplesoft PIAs(pt853) members. and I use httpd Apache as RPS to access Weblogic server cluster,and try to test the sateful failover for peoplesoft application. 

I can login application with RPS, but the failover not work. the http session can't be failed over the another available member in cluster, the transaction was interrupted by terminated cluster member. 

I checked plugin proxy log and weblogic server log, but there are not obvious error in the log. 

I would appreciate it if you can give me the right direction where I can do some research for resolving this issue.