Basically, I changed my display name in launcher_profiles.json and then when I tried to play on a server it says not authenticated to minecraft.net can somebody help me!
Fix: Change your name back!
You should not be changing your name in the launcher_profiles.json. Ever.
If you want to change your name do this:
Log in with your original name (The one you had before you changed it)
Next to your name click on change
Put in your new name, and then your password underneath
This will change your name to the new name that you want to use :D
If you have followed the steps above and your name does not change, log in and out of the Minecraft Launcher. It may take some time to process the change