Symantec Dual WAN 460R router connectivity dies every now and then...(Help?)

We have a dual wan router here at our business.. and every once n a
while the router will be in accessible from the outside world, at
least in terms of allowing information to pass through..

IE: We have a web server that sits on the inside of the firewall..
during these times that website cannot be accessed.. ie: page cant be
displayed etc..

However, if i connect to the router via its dns name.. i can in fact
connect

We have the secondary wan port set as backup (to avoid internal issues
with going to secure websites which complain due to multiple
connections from different ips)..

So when the outside to inside dies, i merely go into the router (if
I'm on the outside) and take wan2 off of backup and to on state.. then
reverse this and all is fine.

During these periods the connectivity is fine from the inside.

I did notice that in the logs of the router there are a ton of
"blocked port scan attacks" messages.

I'm not sure if someone is running some kind of a attack on the router
and it just decides not to allow traffic to pass through from out to
in when this goes on or something else is happening?

Anyone else had this happen?