Sometimes a router reboot does the trick...

Following a power outage today, I had my Kiwis powering up 5 minutes after the rest of the equipment - including my TP-Link router. They did, and local contact was established, but no remote! I checked IP addresses and the router's config, which hadn't changed at all. I then did the "Check port open" routine, and it returned NO/NO! Now what... All I then could think of, was to reboot the router. Result! This is a problem I haven't had before. I can only assume that the router did not get properly configured the first time it booted up.