This usually happens when the traffic through HTTP port 1812 is not allowed.

For example:

[root@iwsva ~]# iptables -nL | grep 1812
[root@iwsva ~]#

You will need to manually add an iptables rule to allow HTTP traffic on port 1812:

[root@iwsva ~]# iptables -I LOCAL_SERV_IN -p tcp --dport 1812 -j ACCEPT

The iptables entry will look as follows:

[root@iwsva ~]# iptables -nL

Chain LOCAL_SERV_IN (1 references)
target    prot opt source      destination
ACCEPT    tcp -- 0.0.0.0/0     0.0.0.0/0      tcp dpt:1812

After manually adding the iptables rule, it will be possible to access the IWSVA web console via HTTP on port 1812.