Unable to gossip with any seeds - Cassandra Issues

Unable to gossip with any seeds

it appears that the nodes are not able to connect to each other

[11:58] 

as in there is probably a firewall/port issue here

[11:59] 

https://docs.datastax.com/en/datastax_enterprise/4.8/datastax_enterprise/sec/secConfFirePort.html

Check :
[root@cassan02 .cct]# telnet cassan03.myblog.com 7199
Trying 10.24.8.36...
telnet: connect to address 10.xx.xx.xx: No route to host
[root@cassan02 .cct]#
[root@cassan02 .cct]# telnet cassan03.myblog.com 9042
Trying 10.xx.xx.xx ...

telnet: connect to address 10.xx.xx.xx: No route to host

work with your system admin to resolve the firewall issue

Probable error messages you will see from /var/log/cassandra/system.log

INFO  [main] 2016-07-01 06:24:54,569  OutboundTcpConnection.java:97 - OutboundTcpConnection using coalescing strategy DISABLED

INFO  [ScheduledTasks:1] 2016-07-01 06:24:57,731  TokenMetadata.java:433 - Updating topology for all endpoints that have changed

ERROR [main] 2016-07-01 06:25:25,581  CassandraDaemon.java:581 - Exception encountered during startup

java.lang.RuntimeException: Unable to gossip with any seeds

at org.apache.cassandra.gms.Gossiper.doShadowRound(Gossiper.java:1345) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at org.apache.cassandra.service.StorageService.checkForEndpointCollision(StorageService.java:541) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at org.apache.cassandra.service.StorageService.prepareToJoin(StorageService.java:794) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at org.apache.cassandra.service.StorageService.initServer(StorageService.java:726) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at org.apache.cassandra.service.StorageService.initServer(StorageService.java:617) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:389) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at com.datastax.bdp.server.DseDaemon.setup(DseDaemon.java:336) ~[dse-core-4.8.6.jar:4.8.6]

at org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:564) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at com.datastax.bdp.DseModule.main(DseModule.java:74) [dse-core-4.8.6.jar:4.8.6]

INFO  [Daemon shutdown] 2016-07-01 06:25:25,582  DseDaemon.java:420 - DSE shutting down...

WARN  [StorageServiceShutdownHook] 2016-07-01 06:25:25,582  Gossiper.java:1462 - No local state or state is in silent shutdown, not announcing shutdown

INFO  [Daemon shutdown] 2016-07-01 06:25:25,582  PluginManager.java:106 - All plugins are stopped.

INFO  [StorageServiceShutdownHook] 2016-07-01 06:25:25,583  MessagingService.java:734 - Waiting for messaging service to quiesce

INFO  [ACCEPT-/10.24.8.36] 2016-07-01 06:25:25,583  MessagingService.java:1018 - MessagingService has terminated the accept() thread

ERROR [Daemon shutdown] 2016-07-01 06:25:25,587  CassandraDaemon.java:229 - Exception in thread Thread[Daemon shutdown,5,main]

java.lang.AssertionError: null

at org.apache.cassandra.gms.Gossiper.addLocalApplicationStateInternal(Gossiper.java:1415) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at org.apache.cassandra.gms.Gossiper.addLocalApplicationStates(Gossiper.java:1439) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at org.apache.cassandra.gms.Gossiper.addLocalApplicationState(Gossiper.java:1429) ~[cassandra-all-2.1.13.1218.jar:2.1.13.1218]

at com.datastax.bdp.gms.DseState.setActiveStatusSync(DseState.java:252) ~[dse-core-4.8.6.jar:4.8.6]

at com.datastax.bdp.server.DseDaemon.preStop(DseDaemon.java:428) ~[dse-core-4.8.6.jar:4.8.6]

at com.datastax.bdp.server.DseDaemon.safeStop(DseDaemon.java:438) ~[dse-core-4.8.6.jar:4.8.6]

at com.datastax.bdp.server.DseDaemon$1.run(DseDaemon.java:684) ~[dse-core-4.8.6.jar:4.8.6]

at java.lang.Thread.run(Unknown Source) ~[na:1.8.0_74]