Troubleshooting Apache Cassandra connection problem with nodetool

I have an Apache Cassandra cluster with five nodes. When I run "nodetool status" command, it shows all the five nodes in the cluster. But when I run a command like "nodetool -h [login to view URL] decommission" or even "nodetool -h [login to view URL] status", I get an error saying "Failed to connect to [login to view URL]:7199. I have tried everything that the online documentation says, and various replies on stackoverflow suggest, but no success. I have disabled Firewall and still no luck. Perhaps I am missing something somewhere. I would like someone to help me troubleshoot this problem, using TeamViewer. For an experienced Apache Cassandra professional, it should be easy to solve.