Minecraft Bukkit Server failed bind to port?

I'm trying my Bukkit Server IP to get static on No-IP. First of all, everything runs smoothly under localhost and the Hamachi IP. I have the port 25565 in the FritzBox and my firewall as UDP and TCP share, the new IP of noip inserted into the server and when I start the server now comes the message "failed bind to port" and the comment that probably already another Server is running on the port.

Since I use a D-Lan adapter I thought that there's a problem, but I have now tried directly via LAN to the FritzBox but it comes the same error.

I also tried other ports to free and have changed everything, and with the ports 77747 and 25566 tried. Both changes unsuccessful.

In the No-IP program, all connections can be made. There seems to be no problem.

I already checked the cmd window if the port is in use, but no.

Eigendlich remains but only still my PC blocked the port, but where can I check and change. Or does anyone have other solutions?

Does the server but no IP address, he can use all but those available to him or not?

Thanks, I did not know that I can leave the line for the port also free.

So the server starts completely, I come to the server when I connect via the No Ip ******. Hopto.org, the same time to test if others can do the same.

* IP (not port line)

If you can connect through the dyndns, others can.

New problem, I just want to do a rejoin and the server can no longer be found at the address, not even by friends, I still see it under localhost.

I have not changed anything, the IP line is still empty in the server.properties

Restart the server, check again, if the IP is empty and the port is still used, as planned.

Server restarted several times, PC too, IP is empty, port is still 25565, have also times the properties file deleted, the server starts normally but I can't enter it under the IP

By remote diagnosis, I can now only guessing… Does your PC still have the same internal IP or was this changed?

Is still the same, have also clicked on update a few times with noip

Hm, so either the port is suddenly different (why ever) or the internal IP has changed. I can't explain that otherwise.