SO my Arlo was connected to a Wifi Extender and it worked fine for several months. Then that wifi extender died. I connected it to an other extender but it could't connect to any of my devices. I tried to connect it to my main router. That didn't work either. I removed the devices from my account. I reset the base station many times. The app still can't discover the base station.
A solid blue LED means the base station is connected to the internet.
When you say you reset the base station before trying to add it back to your account, did you follow these reset instructions: How can I reset my Arlo SmartHub or base station to the default values?
Thanks. I already did but wasn't much help. He suspected my ports were closed. I tried to open the ports 80 and 443 in my router yesterday. Wasn't sure if I was doing it right too. Anyway looks like the port forwarding finally worked today because it just started working again. Long month. Thanks.