Error response code 503

1 on kibana web interface appears that error message > No result data
2 on redhat 6 logstash service down automatically
3 ithere are n the logstash log file errors
a)too many attempts at sending even,dropping
b)retrying failed action with response code 503

the kibana version is 4.1.2
the version of elasticsearch is 1.7.2 lucene_version 4.10.4