Load Balancing Cluster not working with Apache HTT

I am certifying my application on JBoss EAP 7. My application works on standalone mode but in cluster mode, my application gets deployed but I am unable to login. I am again re-routed to login url.
I have setup cluster using mod_cluster.

There is no error log in Load Balancer Server logs neither on individual nodes of the cluster.
In my test environment, my load balancer and 2 server nodes are on same machine. I have given JBoss nodes different ports and instance-ids to differentiate the nodes.
I am sharing my mod_cluster.conf and JBoss standalone-ha.xml extracts from one of the nodes in cluster. Thanks in advance..
Please do not downvote the question, please send any suggestions in comments to rephrase the question.

Following are the snippets in standalone-ha.xml file:

Modcluster settings are:

    <subsystem xmlns="urn:jboss:domain:modcluster:2.0">
    <mod-cluster-config advertise-socket="modcluster" proxies="proxy1" balancer="testcluster" advertise="true" connector="ajp">
        <dynamic-load-provider>
            <load-metric type="busyness"/>
        </dynamic-load-provider>
    </mod-cluster-config>  
</subsystem>

Undertow settings are:

    <subsystem xmlns="urn:jboss:domain:undertow:3.1" instance-id="node1">
    <buffer-cache name="default"/>
    <server name="default-server">
        <ajp-listener name="ajp" socket-binding="ajp"/>
        <http-listener name="default" socket-binding="http" redirect-socket="https"/>
         <host name="default-host" alias="localhost">
            <location name="/" handler="welcome-content"/>
            <filter-ref name="server-header"/>
            <filter-ref name="x-powered-by-header"/>
        </host>
    </server>
   <servlet-container name="default">
        <jsp-config/>
        <websockets/>
    </servlet-container>
    <handlers>
        <file name="welcome-content" path="${jboss.home.dir}/welcome-content"/>
    </handlers>
    <filters>
        <response-header name="server-header" header-name="Server" header-value="JBoss-EAP/7"/>
        <response-header name="x-powered-by-header" header-name="X-Powered-By" header-value="Undertow/1"/>
    </filters>
</subsystem>

Contents of Socket Binding Group are:

<socket-binding-group name="standard-sockets" default-interface="public" port-offset="${jboss.socket.binding.port-offset:0}">
    <socket-binding name="management-http" interface="management" port="${jboss.management.http.port:9990}"/>
    <socket-binding name="management-https" interface="management" port="${jboss.management.https.port:9993}"/>
    <socket-binding name="ajp" port="${jboss.ajp.port:8009}"/>
    <socket-binding name="http" port="${jboss.http.port:8080}"/>
    <socket-binding name="https" port="${jboss.https.port:8443}"/>
    <socket-binding name="jgroups-mping" interface="private" port="0" multicast-address="${jboss.default.multicast.address:230.0.0.4}" multicast-port="45700"/>
    <socket-binding name="jgroups-tcp" interface="private" port="7600"/>
    <socket-binding name="jgroups-tcp-fd" interface="private" port="57600"/>
    <socket-binding name="jgroups-udp" interface="private" port="55200" multicast-address="${jboss.default.multicast.address:230.0.0.4}" multicast-port="45688"/>
    <socket-binding name="jgroups-udp-fd" interface="private" port="54200"/>
    <socket-binding name="modcluster" port="0" multicast-address="224.0.1.105" multicast-port="23364"/>
    <socket-binding name="txn-recovery-environment" port="4712"/>
    <socket-binding name="txn-status-manager" port="4713"/>
    <outbound-socket-binding name="mail-smtp">
        <remote-destination host="localhost" port="25"/>
    </outbound-socket-binding>
    <outbound-socket-binding name="proxy1"> 
    <!-- host and port number of the load-balancer.  -->
        <remote-destination host="x.x.x.x" port="81"/>
    </outbound-socket-binding>
 </socket-binding-group>

Contents of mod_cluster.conf are as follows:

LoadModule proxy_cluster_module modules/mod_proxy_cluster.so
LoadModule cluster_slotmem_module modules/mod_cluster_slotmem.so
LoadModule manager_module modules/mod_manager.so
LoadModule advertise_module modules/mod_advertise.so

MemManagerFile "//httpd2.4.6Home/var/cache/mod_cluster"

<IfModule manager_module>
    Listen 81
    <VirtualHost *:81>
    <Directory />
        Require all granted
    </Directory>
    <Location />
        Require all granted
    </Location>
    <Location /mod_cluster_manager>
        SetHandler mod_cluster-manager
        Require all granted
    </Location>
        KeepAliveTimeout 60
        MaxKeepAliveRequests 0
        ManagerBalancerName testcluster
        AdvertiseFrequency 5
        ServerAdvertise on
        EnableMCPMReceive
    </VirtualHost>
</IfModule>

Basically you have two options - either create a cluster using JBoss own domain mode or extend you standalone configuration to contain required elements for session replication and sso.

In domain mode, most of the configurations are already present in EAP7 - just extend domain-full-ha profile.

Required changes include enabling distributable flag in your web app web.xml - simply add <distributable/> to your web.xml. Next add single sign on flag to your undertow system:

  <host name="default-host" alias="localhost">                                                           
     <location name="/" handler="welcome-content"/>                                                     
     <filter-ref name="server-header"/>                                                                 
     <filter-ref name="x-powered-by-header"/>                                                           
     <single-sign-on/>    <!-- FIXME:  enable SSO here -->                                                                              
   </host>

And enable cache container required for clustered SSO to work - this requires Infinishpan subsystem, which you might now have, if you only extended standalone-ha profile. If you do not see Infinispan subsystem, have a look at standalone-full of standalone-full-ha profiles. If you do not have it already, add web cache:

 /subsystem=infinispan/cache-container=web/distributed-cache=concurrent:add
 /subsystem=infinispan/cache-container=web/distributed-cache=concurrent/store=file:add

Again, if you use full-ha profile of either standalone or domain mode, you will probably have these already.

Also you do not mention, if you use JBoss security domain for authorization or not. In case you use some custom auth mechanism, make sure you set the session cookie or tokens correctly - for correct domain and context etc.