Problem/Bug Error connecting to server.

A bit of backstory,
I am trying to run a server off an old laptop with ubuntu, everything is set up and I have the ports forwarded. However, whenever I try logging in to the server I get an error as follows:


And in the server console it says "ERROR: Couldn't verify username because servers are unavailible."

If I go into server.properties and set online-mode=false it allows me to join. Before you ask, no this is not a cracked account, I can connect to any public server.

My friends get an error such as: io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information:


I am really stuck on how to solve this, I have ran port checkers and it shows that they are closed but I don't understand how they are closed if the ports are forwarded. For ISP I use Shaw internet, I'm not sure if they block ports from being opened.

Any help or suggestions would be greatly appreciated. If you have an idea don't hesitate to reply. Thanks!

 

Thanks for the support, this has been an ongoing issue for 2 days.

Bump, unsolved. Still unsolved. Day 4 unsolved.

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