Minecraft server is having port issues, and I can't figure out what's wrong?

My firewall isn't blocking it, I know i port forwarded it correctly, but www.canyouseeme.org says the port 25565 is closed. I can connect with my internal up and local host, but everyone else and I can't connect with my external ip. (I'm using the latest 1.6.4 build bukkit has, because I have problems with 1.7.9).

Www.canyouseeme.org is not reliable. I have game servers running that people can join, but it says it can't see me.

If your ISP is not blocking the port, then you did something wrong. Period.

If the server is running on the default port, and if the port is forwarded properly and if there's no firewall in the way, then people would be able to join. Period.

Go back to the computer running the server and make sure the server really is running on the port you think it is. See what the computers Ip address is. Make sure there's no firewall in the way. Make sure you forwarded the correct port to the correct ip address. Make sure your router has no firewall in the way.

My guess would be you didn't forward the port properly. That is the most common cause of this.