No response from the server

Hi All
I have been following your install instructions for and Install on Redhat 7 (Centos 7)
I can do this test
sudo docker run -p 3838:3838 openanalytics/shinyproxy-demo R -e ‘shinyproxy::run_01_hello()’
That works fine
However when I try and run shinyproxy. it works as well and I can see it is listening on the allocated port, 8080
But how do you debug it, or get anything useful out of it.
If I just try and telnet to localhost 8080 I get error 400


2019-09-20 15:16:07.725 DEBUG 10797 — [tiveProxyKiller] o.s.c.e.PropertySourcesPropertyResolver : Found key ‘proxy.admin-groups’ in PropertySource ‘configurationProperties’ with value of type String
2019-09-20 15:16:07.726 DEBUG 10797 — [tiveProxyKiller] o.s.c.e.PropertySourcesPropertyResolver : Could not find key ‘proxy.admin-groups[0]’ in any property source
2019-09-20 15:16:23.434 DEBUG 10797 — [ XNIO-2 I/O-2] : UT005014: Failed to parse request

java.lang.IllegalArgumentException: UT000163: Invalid token 8
at io.undertow.server.Connectors.verifyToken( ~[undertow-core-1.4.22.Final.jar!/:1.4.22.Final]
at io.undertow.server.protocol.http.HttpRequestParser$$generated.handleHttpVerb(Unknown Source) ~[undertow-core-1.4.22.Final.jar!/:1.4.22.Final]
at io.undertow.server.protocol.http.HttpRequestParser.handle( ~[undertow-core-1.4.22.Final.jar!/:1.4.22.Final]
at io.undertow.server.protocol.http.HttpReadListener.handleEventWithNoRunningRequest( [undertow-core-1.4.22.Final.jar!/:1.4.22.Final]
at io.undertow.server.protocol.http.HttpReadListener.handleEvent( [undertow-core-1.4.22.Final.jar!/:1.4.22.Final]
at io.undertow.server.protocol.http.HttpReadListener.handleEvent( [undertow-core-1.4.22.Final.jar!/:1.4.22.Final]
at org.xnio.ChannelListeners.invokeChannelListener( [xnio-api-3.3.8.Final.jar!/:3.3.8.Final]
at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady( [xnio-api-3.3.8.Final.jar!/:3.3.8.Final]
at org.xnio.nio.NioSocketConduit.handleReady( [xnio-nio-3.3.8.Final.jar!/:3.3.8.Final]
at [xnio-nio-3.3.8.Final.jar!/:3.3.8.Final]

If I just a browser, the browser just sits and eventually gives error 500.
How do I find some information to tell me which part of the pipeline is broken?

Ok, I managed to connect to the webpage and login. Yay
However now it give me error 500 , container failed to load
Which is weird because I can see in the logs on the server that it did load
Although it seemed to start listening on port 3838. This is for the demo docker image btw, i’m trying to get to load