Bottom Line Up-Front: Delete your Wi-Fi connection from within your Mac's Network Preferences and re-add a new one.
Background of Problem: Your Wi-Fi is working for other devices, and your Mac even connects to your Wi-Fi, but you get no internet. This might be because of an IP problem.
Here's the quick fix: Go to the Network Preferences menu on your Mac and remove and restore the Wi-Fi connection. This quick video shows you how to quickly do that.
Please tell me if it worked for you. A sub and a like would help me grow my channel and be much appreciated.
Stay ready,
Nick.