Security camera viewing on local network and remote viewing

This might be the wrong equipment for the application, but this is what was purchased and we would like to get it working.

Here is the configuration:

Cable modem is attached to WAN1 and the FVS336G is set for DHCP

A 24 port Netgear gigabit switch is connected to the VLAN1 port on th FVS336G (this is the only port used on the FVS336G)

A Netgear Nighthawk wireless router is attached to one of the ports on the gigabit switch and is set for Access Point mode

A surveilence camera system is connected to one of the ports on the gigabit switch and is set for 192.168.2.199

Various computers are connected to other ports on the gigbit switch.

Smartphones, tablets and laptops connect wirelessly to the Nighthawk router.

The FVS336G is configured to hand out ip addresses in the range of 192.168.2.200 through 192.168.2.254

This issue we are having is that the smartphones and tablets that use apps to view the security camera images have to be set for 192.168.2.199 when connected to the local network  When we are not on the local network, they need to be changed to the IP address provided by the cable modem or the dyndns address that is assigned to that ip address.  When they are connected to the local network, leaving them set to the cable modems address or the dyndns address results in a connection failure.

Some of the looking we have done says that this is caused by a NAT loopback issue and others say that this is normal and has to be changed each time.  I am lost at this point since others i have spoken to about this problem do not have the issue with their equipment.  They are able to leave the smartphones and tablets set for the external DNS or ip address and it resolves regardless of being on or off they wireless network.

Any help would be appreciated.

Thank you