We have two exchange sites, I am trying to allow OWA in one site to send email users to either site, depending on where there mailbox is. I set up http virtual directories on front and backend servers and pointed the new directories to the correct domains. When trying OWA to the remote site, I get a Service Unavailable error. When I open exchange system manager and click the remote site, server and http virtual server properties, it says the rpc server is not available, and there is a question mark over the http virtual directory. However I can ping the server fine, and all necessary services are running. Anyone know what could cause this.