You can run the Minecraft server, right? There are no port binding problems, Java is in your system path, and if you're using a batch file, it's not exiting with an error that's to fast for you to see, right?
Did you make sure to whitelist Java in Windows Firewall? Even if you allow TCP port 25565 through the firewall, if Windows is still blocking Java then nothing will work (Windows should ask you if you want to whitelist it when the firewall detects the server is running, I think).
You port forward through your modem/router by logging in to it through your gateway IP, correct? If you search for your WAN IP in your modem (that is, an IP address that doesn't look like your computer's one, i.e. one that doesn't look like 192.168.x.y), does it match up with what canyouseeme.org is reporting?
You can completely eliminate (or mostly, anyway) any problems on your network and Windows/Antivirus Firewall by using another computer or a smart phone (app) to connect to TCP port 25565.
Admittedly, if you're confident enough that it's not a firewall problem, then perhaps the problem is with your ISP.