I have not read anything except a few sentences, but still may be of use. Make sure to see if your router is changing your internal IP address. If you have your port forwarding set up for a specific internal IP address, you may need to set up a static IP. An alternative is to always check your current internal IP address with cmd ipconfig /all ...and change your port forward accordingly each time before you start a server. It'll be easier to set up a static IP address...but if you have internet connection problems you may forget that you have done that. Just be sure to switch your IP back to automatic if you have connection problems much later. You then can switch it back to static for Blockland once it's solved.
