We don't use sme-server(6.0) as a mailserver, only as a dhcp,proxy,dns-server. We have an extern mailserver through webmail. Each time several users want to log on at the same time,we get errors from de webmailserver. I have already posted the errors to the webmailservermanager. He thinks that the errors we are receiving have something to do with our proxyserver because we are the only ones with this problem.He thinks that we have to disable the caching on our sme-server.