PROBLEM: ARERR 90 for an ARServer FQDN server name that is not resolvable on the network.

The ar.cfg file (on Windows) or ar.conf (on UNIX) is using both server name parameters:

Server-Connect-Name: shortname (actual host name)
Server-Name: alias name

However in various operations, such as running a report, user may see the error on their browser client and Remedy Admins may see the following in the arjavaplugin log (***Note: using "remedy.bmc.com" as an example for the FQDN of the servername):

Mar 9, 2017 4:35:45 PM - SEVERE (com.remedy.log.SERVLET) : (Thread 63) com.remedy.arsys.log.Log log GoatException during NDXRequest:= > ARERR [90] Cannot establish a network connection to the AR System server : remedy.bmc.com : RPC: Success
at com.remedy.arsys.backchannel.SetEntryListAgent.createNewEntry(SetEntryListAgent.java:73)
at com.remedy.arsys.backchannel.SetEntryListAgent.process(SetEntryListAgent.java:280)
at com.remedy.arsys.backchannel.NDXRequest.processRequest(NDXRequest.java:131)
at com.remedy.arsys.backchannel.NDXRequest.<init>(NDXRequest.java:103)
at com.remedy.arsys.backchannel.EntryListBase.<init>(EntryListBase.java:75)
at com.remedy.arsys.backchannel.NDXSetEntryList.<init>(NDXSetEntryList.java:15)
at com.remedy.arsys.backchannel.SetEntryListAgent.<init>(SetEntryListAgent.java:60)
at com.remedy.arsys.backchannel.NDXFactory.handleRequest(NDXFactory.java:47)
at com.remedy.arsys.stubs.BackchannelServlet.doRequest(BackchannelServlet.java:143)
at com.remedy.arsys.stubs.GoatServlet.postInternal(GoatServlet.java:122)
at com.remedy.arsys.stubs.GoatHttpServlet.doPost(GoatHttpServlet.java:61)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.assurebridge.remedy.sp.SPAuthenticationProcessingFilter.doFilter(SPAuthenticationProcessingFilter.java:470)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:436)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2517)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2506)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: ERROR (90): Cannot establish a network connection to the AR System server; golddevar01.federalcloud.local : RPC: Success
at com.bmc.arsys.apitransport.ApiProxyJRpcBase.verifyStatus(Unknown Source)
at com.bmc.arsys.apitransport.ApiProxyJRpcBase.a(Unknown Source)
at com.bmc.arsys.apitransport.ApiProxyJRpcBase.arCall(Unknown Source)
at com.bmc.arsys.api.ProxyJRpc.ARCreateEntry(Unknown Source)
at com.bmc.arsys.api.ARServerUser.createEntry(Unknown Source)
at com.remedy.arsys.backchannel.SetEntryListAgent.createNewEntry(SetEntryListAgent.java:69)
... 35 more

Some entries in the Server Group Operations Ranking form indicated the incorrect Servername with the wrong domain name. Deleting the incorrect entries did not resolve the errors but this but doing so was still prudent to ensure proper Server Group configuration for Rankings.

This knowledge article may contain information that does not apply to version 21.05 or later which runs in a container environment. Please refer to Article Number 000385088 for more information about troubleshooting BMC products in containers.

You can also verify what ARServer thinks the host name is by running a GSI (Get Server Information API call) in Driver. 

For Example

After you have run the "init", logged in and set the server port if needed:

Command: gsi 
GET SERVER INFO 
Number of server info operations (0): 2 
Operation (1-401) (1): 48 
Operation (1-401) (1): 49 

ARGetServerInfo results 
ReturnCode: OK 
Server Info List : 2 items 
Server Info Struct: SERVER HOSTNAME 
Value: (char) remedy 
Server Info Struct: SERVER FULL (DNS) HOSTNAME 
Value: (char) remedy.bmc.com
Status List : 0 items 

To resolve this, the system has to be moved to be a member of the correct domain or you can use the following parameter in the ARServer's config file:

Domain-Name: <servername.domain.com>

Domain-Name is documented as follows:

New domain name portion of the fully qualified server name. 
By default, a server determines the domain name from the network interface. 
In rare cases, this method does not produce the desired result because of 
unexpected network card configurations. In those cases, you can use this 
option to override the domain name derived from the network interface.

ARS 8.1 ar.cfg or ar.conf options C-D
ARS 9.1 ar.cfg or ar.conf options C-D