Firestick "Connected to WiFi but no internet": HELP?!

My signal is "very good" and the stick connects to WiFi, but it continues to say "no internet." I am also experiencing this with my Kindle Fire; as is shows the WiFi symbol, except with an exclamation point in it. Additionally, 2 phones, 1 laptop and 1 PlayStation are all connected to the internet without issues at all.

I have tried restarting, factory reset and restarting my router. Is there anyone else who has had, or is currently having this problem? What could possibly be the issue and how can I go about resolving it? All help is HIGHLY appreciated!!!