VDP Cannot Connect To Web Client "MIME media type application/octet-stream was not found"

Yet another issue. You will see this generic message in web client when you connect to the web client VDP plugin:

As usual, we always check the web client logs on the vCenter for more information. And in this case, below was the back trace:

[2018-01-24T15:02:43.924Z] [ERROR] -0:0:0:0:0:0:0:1-9090-exec-9 70467127 102381 201761 com.sun.jersey.api.client.ClientResponse A message body reader for Java class com.emc.vdp2.model.error.VdrError, and Java type class com.emc.vdp2.model.error.VdrError, and MIME media type application/octet-stream was not found
[2018-01-24T15:02:43.924Z] [ERROR] -0:0:0:0:0:0:0:1-9090-exec-9 70467127 102381 201761 com.sun.jersey.api.client.ClientResponse The registered message body readers compatible with the MIME media type are:
application/octet-stream ->
com.sun.jersey.core.impl.provider.entity.ByteArrayProvider
com.sun.jersey.core.impl.provider.entity.FileProvider

[2018-01-24T15:02:43.924Z] [WARN ] -0:0:0:0:0:0:0:1-9090-exec-9 70467127 102381 201761 com.emc.vdp2.api.impl.ActionApi Caught UniformInterfaceException [POST https://192.168.246.10:8543/vdr-server/auth/login returned a response status of 400 Bad Request], recieved HTTP response: [400] com.sun.jersey.api.client.UniformInterfaceException: POST https://192.168.246.10:8543/vdr-server/auth/login returned a response status of 400 Bad Request
at com.sun.jersey.api.client.WebResource.handle(WebResource.java:688)
at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74)
at com.sun.jersey.api.client.WebResource$Builder.post(WebResource.java:560)
at com.emc.vdp2.api.impl.ActionApi.connectVDR(ActionApi.java:40)
at sun.reflect.GeneratedMethodAccessor2344.invoke(Unknown Source)

[2018-01-24T15:02:43.933Z] [WARN ] -0:0:0:0:0:0:0:1-9090-exec-9 70467127 102381 201761 org.springframework.flex.core.DefaultExceptionLogger The following exception occurred during request processing by the BlazeDS MessageBroker and will be serialized back to the client: flex.messaging.MessageException: com.sun.jersey.api.client.ClientHandlerException : A message body reader for Java class com.emc.vdp2.model.error.VdrError, and Java type class com.emc.vdp2.model.error.VdrError, and MIME media type application/octet-stream was not found
at flex.messaging.services.remoting.adapters.JavaAdapter.invoke(JavaAdapter.java:412)
at com.vmware.vise.messaging.remoting.JavaAdapterEx.invoke(JavaAdapterEx.java:72)
at flex.messaging.services.RemotingService.serviceMessage(RemotingService.java:180)
at flex.messaging.MessageBroker.routeMessageToService(MessageBroker.java:1472)

The issue is due to a corrupted server.xml for the tomcat library. Due to this, none of the vCenter users would be able to connect or only domain users might face this issue.

To fix this:
1. Download the patched server.xml file from this link here:
https://github.com/happycow92/Patches

2. Copy the file to the /root of VDP via WinSCP

3. Backup the original file:

# cp -p /usr/local/avamar-tomcat/conf/server.xml ~/server.xml.bak

4. Remove the old server.xml file:

# rm -f /usr/local/avamar-tomcat/conf/server.xml

5. Replace the patch file in the conf path:

# cp -p ~/server.xml /usr/local/avamar-tomcat/conf

6. Update permissions and ownership:

# chown root:root server.xml && chmod 644 server.xml

7. Restart tomcat service

# emwebapp.sh --restart

The connection will take a while now since it needs to rebuild the cache, but it will be successful.

Hope this helps.