Trace details can't be shown in the Phoenix Tracing Web Application

298752 [qtp440434003-46] WARN org.eclipse.jetty.servlet.ServletHandler  - /trace/
java.lang.RuntimeException: The passed parentId/traceId is not a number.
        at org.apache.phoenix.tracingwebapp.http.TraceServlet.searchTrace(TraceServlet.java:117)
        at org.apache.phoenix.tracingwebapp.http.TraceServlet.doGet(TraceServlet.java:67)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:648)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:455)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
        at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:559)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1072)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:382)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1006)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
        at org.eclipse.jetty.server.Server.handle(Server.java:365)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:485)
        at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:926)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:988)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:635)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
        at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:627)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:51)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NumberFormatException: null
        at java.lang.Long.parseLong(Long.java:552)
        at java.lang.Long.parseLong(Long.java:631)
        at org.apache.phoenix.tracingwebapp.http.TraceServlet.searchTrace(TraceServlet.java:114)
        ... 26 more