Minecraft - Authentication servers aren't connecting to my Ubuntu

Server Information:

OS: Ubuntu 16.04.1 LTS
Java: 1.8.0_45

For some odd reason, I can't join any of my Minecraft servers because the game says Authentication failed (This error is printed when the server hosting the game can't connect to the session servers of the game, you can see at help.mojang.com all their servers are online and I shouldn't be having this problem unless there's a network issue on my end). I am able to join other servers just fine, but mine don't work. I have ping-ed google successfully using Ubuntu's ping program. I had one of my friends join the same server and were unsuccessful. I have copied files from another Ubuntu 16 server, I can join those Minecraft servers just fine, I pasted them on to the suspect server and started it, it did not work. It has to be something to do with it not communicating with the authentication servers or something network wise as the good dedicated is on a totally different network.

Please note: I have tried both my domain and the normal IP as well as no multicraft and multicraft. If you're curious, I have tried 1.7.10, 1.8.9 and 1.11.2 versions of Minecraft, none worked.

If you can help, it would be much appreciated.

1 Answer

After months of research and help from wonderful people here at Superuser, I have finally got the servers to be able to accept premium players on online mode. I no longer have any SSL errors. Here's what I did:

After @Seth gave me a link to another post related to a recent error I got, I put a simple command line in the console and the servers were able to start on online mode.

Link:

Command line code:sudo update-ca-certificates -f