ipad not seeing wifi router

My Ipad isn't seeing my wifi router. It keeps searching for it. It shows up in the list of nearby wifi and i put in the router password but it doesn't connect. for some reason.
I did set up Apple Tv yesterday, but i changed nothing on my router. (My Kindle Fire
also is not connecting.) It was working fine before.
The Apple tv is connecting fine to my router. Any ideas? Thanks

Try shutting off the power to your router for a few seconds and plug it back in. Let it reboot.

If that doesn't work, check the settings on your router. What security settings are you using?

Does it work properly if you turn the security off temporarily?

Did your Kindle ALSO work fine before you set up the Apple TV?

What brand and model of router is it?