Ring Door Bell 3 Plus - attempted to install today and after going thru setup for WIFI Connection, when I attempted to connect to Wifi - I was able to select the network I needed to connect to - signal strengh on my phone for that network was very good, but everytime I went thru the setup process, it failed - the final connection step where it says “Ring Doorbell is trying to connect to your network” failed every time - with the lights on the doorbell flashing (two lights on the right side) were flashing - and ultimately, the doorbell wanted me to try again. I did this at least ten times and it failed everytime. I even brought the doorbell into the house and attempted to set it up while sitting within 5 feet of the router and it failed. (Meanwhile, I can easily connect my phone and PC to that router and get a great internet connection each time. The Router is the Netgeat 1900 - a pretty standard router that I am using to extend the Wifi Single in my house. Works great when any other device I own needs to connect - but will not connect to the Ring Doorbell 3 + ??? I am at a complete loss ???
Sorry to hear about this @Mocsab! If you have other devices in your home connecting and operating on your network, your Ring device should certainly complete a setup. Good call on attempting this setup closer to the router.
Try enabling a standard 2.4 Ghz guest network on your router with standard SSID and password, to see if this might allow it to complete setup. On the last step of the setup, in the Ring app, there is also an add hidden network option which will allow you to manually enter your network information.
If the Doorbell is still not connecting, please check out our help center article on ports and protocols to see if this might help! 
After repeated attempts, I multiple resets and changing location of router and extended network device, the I was finally able to connect and maintain connections for all Ring devices. I i am hopeful that tbi gs will be stable for a while… Time will tell. I thanks for your assistance.