When using Policy Manager from 10.0 connecting to 10.1 it fails to connect if you choose button Generate report
And review the exception report you see a failure of,
WARNING: <html><center><b>Cannot connect to the gateway <HostName>.</b>
<br> Please check your connection settings and application log for details.<br>
If the problem persists, please contact your network administrator.</center></html>
org.springframework.remoting.RemoteAccessException: Could not deserialize result from HTTP invoker remote service [https://securespangateway/ssg/manager/AdminLogin]; nested exception is java.lang.ClassNotFoundException: org.hibernate.collection.internal.PersistentBag
Release : 10.1
You should ensure that the policy manager utilized is the same as the upgraded application. As JDK is upgraded between versions certain expected class and functions may mismatch.
So ensure you use a 10.1 policy manager to connect to policy manager 10.1.