1.8 Server not working anymore

Hello and thanks for reading already. I ran my server and it said Couldn't bind to port! I found out my ipv4 changed... So I changed it in the serverproperties.yml and ran it again, it worked but I couldn't connect with my external ip now... I portforwarded 5 times but nothing happened. My firewall is ON and I allowed TCP and UCP (25565) in firewall. I put my ipv4 and not my default gateway in the server properties and the portforward thing. It just doesn't work. I can connect with localhost and my ipv4 but not ipv6. Any idea what's happening? A few weeks ago everything was just fine ;-;

Please respond xD

Bump D:

BUMP

EDIT by Moderator: merged posts, please use the edit button instead of double posting.