Is my router blocking ports?

RE 1: You're absolutely certain? Cause nothing else I say here is going to be useful if you're not absolutely certain you've done this first step. Keep in mind you have to port forward on your router AND open those rules on your computers. Not the same process. Keep in mind on the computers, you need to check Inbound/Outbound, and DO IT for the PROGRAM and the PORT.

What kind of server are you running and what steps are you taking to connect? Please list them and any errors it gives you.

RE 2: You should have a static IP set up on the server for internal use, or its IP can change. No-ip is for the external part of this, not for the internal.

A really quick explanation:
Your network ultimately has 2 groups of IP addresses. There's your external IP, or what the internet at large uses to send data to your router, and from then, onward to your computer. Then there are internal (local) IPs that are used by your router to figure out where something goes.

Think of it like sending mail to a company. The company's building address is the external IP, and then on your letter you have Attention: Department of Redundancy. That's like your internal IP.

The issue is, routers give out internal IPs on a relatively arbitrary basis. So if you have port forwarding set up to a specific internal IP, sometimes the device that's supposed to refer to has a different IP now. A static IP tells the computer to always ask the router for the same address for consistency.

Are you trying to connect to it from inside of your network using the No-IP? That won't work (from inside the network). You can still use that to connect from outside of your network, however.

To get your IP information from your server, assuming it runs Windows:
cmd
ipconfig /all

And you'd be looking for IPv4. Ideally, it should say "(IP Address) <Preferred>". If it doesn't, google how to set up a static IP and follow those instructions on the server. Once you set a static IP, restart the system.

Once you've done that, or during, rather, make a note of what that IP is. You will need to use it to connect to your server from WITHIN your network.

RE 3: The way most routers are designed, they don't allow you to call devices on the network using the Router's external IP, as this is usually used for abuse.

If you're inside your network (at your house, say) you will need to use the local IP of your server, which you can obtain via the methods described above. If you're outside your network, you can use your No-IP Dynamic DNS you have set up.

RE 4: Well, try the above stuff, let me know. Most routers are about the same.