What are the precautions so that StateServer Mode work properly?
Following are some points to remember so that StateServer Mode works properly:-
a) StateServer mode session data is stored in a different method so you must ensure that your objects are serializable.
b) elements in Web.config must be identical across all servers.So this assure you that encryption format is same across all computers.
c) The IIS metabase (\LM\W3SVC\2) should be identical across all servers in that farm.