Tez UI: At times RM return a huge error message making the yellow error bar to fill the whole screen.

We get the following error at times

HTTP ERROR 500
Problem accessing /proxy/application_1446723144814_0186/ws/v2/tez/tasksInfo. Reason:
Connection to http://c6401.ambari.apache.org:44065 refused
Caused by:
org.apache.http.conn.HttpHostConnectException: Connection to http://c6401.ambari.apache.org:44065 refused
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:190)
....