Many suggestions. Extenders can be a bit finicky to wifi interference or location. Sometimes simple things can fix them, other times a full reset can fix them. First some extra details for when you respond and then I'll go over troubleshooting.
1. What firmware is on your EX2700?
2. What router are you using? Firmare on router?
3. It sounds like the extender is broadcasting since you can connect. On the front of it is some led's. The router link led is on the top left. What is it doing? If its off, the extender isn't linked back to the router. That'd be the problem if its off. You want that light to be green which means best connection. Amber is good, red is poor. Always try to get it green as the link from the device back to the router is key.
A couple of thoughts/suggestions. Extenders can suffer from interference. Whether someone moved into the area or purchased new gear, if you device was on the edge of its connection, that could have been enough to deteriorate that signal enough if won't connect anymore. A few things you can try to fix it.
1. change channels on the router and extender to a less congested channel. There are free wifi scanners for phones or computers. You can google this to find one. Pick the channel with the least congestion, usually on 1,6, or 11.
2. change location of the extender. I find people put extenders on the very edge of connection. Whenever something causes interference, they loose connection. Another issue can be HVAC, concrete, brick. Sometimes even changed a few feet one way or the other will remove obstacles and boost signal. Play with this location.
3. Still not connecting? You can try resetting the device back to stock and redoing the setup. It sounds like its broadcasting so the radio is working. its just to connect it back to the router.
Here's the link to the support page for this device. It has firmware, quick install guide, and full manual for help.
