[SR-Users] xcap server - http load–balancer: xcap authentication problem

Hello all, I’m using two Kamailio Presence Servers that are also XCAP Servers for the presence and resources management and the Kamailio Dispatcher in order to balance the SIP requestes coming from SIP Client. Then I’m trying to configure a HTTP load–balancer for the xcap/http traffic. I’m testing both Apache and INginx HTTP proxy but I’m facing with a problem related with the Xcap authentication: when a client sends the first xcap request to the http load-balancer, it forwards the request to one of the configured Xcap Server that replies with the 401 response in order to let the client authenticates. So, the client sends the second request with the Digest authentication to the http load-balancer. But, sometimes, the http load-balancer forwards the authenticate request to the second Xcap Server that is not able to authenticate the request. Then the client receive the “Unauthorized” response… Could you please give us some hints about this problem? Thanks in advance, laura