Peekofwar

This is the second time I've had issues connecting to a modded Minecraft server. The first time was my private ATM8 server, which was fine for a while before it kept saying authentication servers were down. I assumed this was caused by something in the ATM8 modpack, and effectively killed that private server. The second time was my main modded server, which neither me or my friend has had any problems with until today when it started saying the authentication servers were down. As a troubleshooting step, I restarted the server, but the error still appeared. My friend mentioned that he was able to connect with no issues to my private vanilla server (hosted on the same machine as my modded server) which suggested to me this could be an issue with Forge. This also reminded me of the ATM8 server issue. So I searched Google for "Forge 1.20.1 unable to authenticate" and found this forum post. Noticed that someone suggested disabling IPv6 in the network adapter settings worked for them. I then proceeded to disable IPv6 on my server's Ethernet adapter (and also wondered why the WIFI adapter was enabled since I've previously disabled that TWICE), and without even needing to restart the dedicated server or the machine itself, I was able to successfully connect with my main computer (which is on the same local network). In short, disabling IPv6 in the network adapter settings fixed the issue.