APM Forms SSO Session Logout Error Page

If you change the rule to have the redirect logic in the response it will allow the backend application to receive the request and close the session there as well. This will ensure both the app and APM session are closed properly.

when CLIENT_ACCEPTED {
    ACCESS::restrict_irule_events disable
}
when HTTP_REQUEST {
    set logout 0
    if {[HTTP::uri]] equals "/Login/logoff"]}{set logout 1}
}
when HTTP_RESPONSE {
    if {$logout}{
        log local0. "logout-request-URI: local URI [HTTP::host][HTTP::uri] redirect to /vdesk/hangup.php3"
        HTTP::header replace "Location" "/vdesk/hangup.php3"
    }
}