Watchguard Firebox X1000

Hello, recently I've had some issue with my firewall. I have to reboot the firewall almost daily. Internet access would stop and I would look at the logs on the firewall and it would log "Kernel ip_masq_new(proto=UDP): No free ports"

I thought maybe a device connected to the network has a virus or something on it causing a lot of outbound traffice, but haven't seen anything out of the ordinary, so I was wondering if the firewall could be just going bad (It's about 8 or 9 years old) or some other reason that is causing this problem with my firewall.

Any help would be appreciated, Thanks!