Introducing a new container to a docker environment interferes with other containers

I’ve spent an awful long time trying to debug this. I have an already populated docker compose file with multiple containers running, all on the same network. The containers consist of a tomcat server(Server A), a hazelcast container, and a hazelcast-mancenter container, and then an apache server. I want to introduce an additional container, which is also a tomcat server(Server B), and for some reason it interferes with the original tomcat server(Server A). Server A never gets to a start up state. Whenever Server B doesn’t get run, Server A works no problem. The moment Server B comes on, Server A poops out. For some reason Server B also attempts to connect to Hazelcast. Hazelcast is in multicast mode, so that might be the reason. Even if I take Server B off the network as the other containers, there is still interference.

What is going on? Shouldn’t the container be isolated?