DataStax agent port setting conflict 

Ensure there are no conflicts with port 7199 used by the DataStax Agent.

If there are problems with OpsCenter, check for conflicts in port settings. The DataStax Agent uses port 7199 by default. If you have not changed the default port, check that Cassandra or another process on the node is not set up to use port 7199.

If you set the DataStax Agent port to a host name instead of an IP address, the DNS provider must be online to resolve the host name. If the DNS provider is not online, expect some intermittent problems.