Nagios ping fails

I recently setup NagiosXI with their provided amazon ami. It was very simple to setup and everything looked good. Added a couple servers and they all could not be pinged from Nagios. I couldn't ping them from Nagios' ping tool. I could ping them from the command line so I knew it was a configuration error.

First I tried:

\$ /usr/local/nagios/libexec/check\_ping -H -c 100,90% -w
CRITICAL - Network Unreachable (  

Then I saw I needed to add the -4 to the command.

\$ sudo vim /usr/local/nagios/etc/commands.cfg  

Go to line 221 and add the "-4"

define command {  
command\_name check\_ping  
command\_line \$USER1\$/check\_ping -4 -H \$HOSTADDRESS\$ -w \$ARG1\$ -c
\$ARG2\$ -p 5  

Then you'll need to restart Nagios.

\$ sudo service nagios restart