set route.all-resources = true already, two clients connect to server, the same user, the same resource, the same machine, first client was disconnected

Hello, I have this problem with two clients connect to server with the same user, the same resource, the same machine. First, I connected with the first client. OK. But then The first client was disconnected when the second client connected to the server.   I have already set route.all-resources = true  .   Any idea how to resolve this? Thanks.