Ring Floodlight Cam can't reconnect to network

I have a floodlight camera that disconnected from the wifi after I installed a new modem. When trying to reconnect, it gets stuck at the "connecting to the internet" step, and says "Something must be wrong with your internet connection" - which there isn't. I've got the same mesh router network (Deco) as was connected to it for the past three years before it disconnected. Same network name and password, no changes. The nearest router to the ring camera is about 6 feet away from it. I've set my network to only 2.4ghz. I've tested multiple other devices connected to each of the three mesh routers, including the one nearest the camera, and all have no issues connecting (getting about 400MB download speed). I have held the button on top for 20 seconds to do a factory reset multiple times. I have unplugged my routers for 30 minutes, and rebooted them a few times just from the app. Nothing seems to allow this camera to get back online. It successfully connects to the wifi signal (or it seems it does - after typing in my wifi password it progresses to the next screen), but when it says "connecting to the internet" is where it stops. I have two other stickup cams that automatically reconnected as soon as the routers came back online. Any ideas?