YARN Exception: Could not determine the proxy server for redirection

[#1]

yarn-site.xml
We are running a cluster with HDP 2.6.3.0-235.
YARN is configured for HA with two Resourcemanagers.

When I run a spark-shell session and want to access the tracking URL of the Spark UI on the server where I started the spark-shell, I get the following error:

HTTP ERROR 500
Problem accessing /. Reason:
    Server Error
Caused by:
javax.servlet.ServletException: Could not determine the proxy server for redirection
	at org.apache.hadoop.yarn.server.webproxy.amfilter.AmIpFilter.findRedirectUrl(AmIpFilter.java:205)
	at org.apache.hadoop.yarn.server.webproxy.amfilter.AmIpFilter.doFilter(AmIpFilter.java:145)
	at org.spark_project.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1676)
	at org.spark_project.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:581)
	at org.spark_project.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180)
	at org.spark_project.jetty.servlet.ServletHandler.doScope(ServletHandler.java:511)
	at org.spark_project.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112)
	at org.spark_project.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.spark_project.jetty.server.handler.gzip.GzipHandler.handle(GzipHandler.java:461)
	at org.spark_project.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:213)
	at org.spark_project.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
	at org.spark_project.jetty.server.Server.handle(Server.java:524)
	at org.spark_project.jetty.server.HttpChannel.handle(HttpChannel.java:319)
	at org.spark_project.jetty.server.HttpConnection.onFillable(HttpConnection.java:253)
	at org.spark_project.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:273)
	at org.spark_project.jetty.io.FillInterest.fillable(FillInterest.java:95)
	at org.spark_project.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93)
	at org.spark_project.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303)
	at org.spark_project.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148)
	at org.spark_project.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136)
	at org.spark_project.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671)
	at org.spark_project.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589)
	at java.lang.Thread.run(Thread.java:745)

However, the shell is working fine and I can also access the Spark UI following the link to the ApplicationMaster in the Resourcemanager UI.

We didn't have this problem before and I assume it started to exist after configuring YARN for HA (using Ambari wizzard).
Attached you can find the yarn-site.xml (exported with Ambari).

Is there any misconfiguration or does somebody know this problem?

Thx,
Alex

[#2]

See https://github.com/apache/spark/pull/22164/files