I opened Minecraft and got onto play.dawncraft.org and I'm on for 2 seconds when I'm booted off

My MInecraft would basically not let me play minecraft, singleplayer or multiplayer.

What I expected to happen was...

To play on a public server (play.dawncraft.org) and when it didn't work I thought it was just my internet so I went onto Singleplayer

What actually happened was...:

I was booted off every time that I attempted to get onto a new Minecraft World and a server I had never played on before
Steps to Reproduce:
1. Open up Minecraft with your username (ironduke2023) and password
2. Join a server under Multiplayer (play.dawncraft.org)
3. Wait two seconds
4. Watch as your Minecraft closes with no warning and without you touching a button