So I wanted to play on a minecraft server , but when i tried to connect it gave me an error and said:"Not authenticated with Minecraft.net"(when i try to connect to hypixel it says:"Failed to authenticate your connection")Problem first occured on a modded version of 1.8.9 , but after making a brand new 1.8.9 vanilla installation the problem still occurs.(Singleplayer still works.)
(Sorry for putting 1.15.2 , but it doesn't let me put 1.8.9)
Edit:Issue occurs on 1.15.2 aswell