Internal web server not working

RB433 running 3.13. I am runing 3 of these new boards with good results. But on one board I am having problems accessing the internal web server. I can not get the routerboard web screen to come up and I can not get the accounting to work. Almost like the internal server is turned off. This is not a firewall issue. No firewall rules on this board. When I try to connect I do see a connection to port 80 in the RB connection list. Any ideas? As I said the other 2 boards are running fine and can be accessed just fine.

TIA

could this be an IP issue? what addresses are on all the interfaces and on the clients? how about NAT or bridging?

Update - I was mistaken on the board. It is a 500 not 400 board. I went ahead and updated to 3.17 last night and for the time being things seem to work.

Thanks