HttpContext.Current.Request.ServerVariables["LOGON_USER"] returns wrong (cached) user

Hi

I have issue with

HttpContext.Current.Request.ServerVariables["LOGON_USER"]

which returns wrong user (user who was running app before).  So far I changed web.config, added

<

cachingenabled="false"enableKernelCache="false"

/>

but it didn't fix the issue.

any help?