Why does my Minecraft server not work?

I've had a Minecraft server for about 5 days now, the first three and a half it was working absolutely fine. Then as of yesterday at around 1:00 pm, my Ip address changed, and even after changing the details in my port forwarding, and even testing the Ip address I give others, it refuses to work for anyone outside of my network.

Can anyone offer any insight?

Added (1). I should also note that only my LAN ip address changed, it went from *.*.*.9 to *.*.*.4,
And while every website lists my Ip address as the same, a quick google search gives me
2601:a:2700:5f3:75ae:215:acd4:4402

You have a dynamic I.P address. It is not recommended to run a server off of a dynamic I.P address. If your i.p address changes that often, you may want to look into one of two options:

1. Http://www.noip.com/ No-Ip essentially gives you a domain name that redirects to your current I.P address. It'll protect from this whole Dynamic I.P situation, but it's still not 100%. If you're just running a server for a couple of friends or whatever, this is definitely the way to go. You don't have to worry about minor inconsistencies when it's just a few friends and you can laugh it off.

2. If you want to host a server for many people to use, and what reliable hosting that doesn't take much effort, you'll need to purchase a web host. Xdawnedx.com/mchost is a fairly good webhost, and they're doing 75% off this month too. Remember, you only need paid hosting if you want a public server. If it's just for your friends/family, disregard this. You can manage with noip.