Nether Not being able to load, Unable to Join Server.

So me and my friends went to the nether made two nether portals next to each other, I went into the right portal landed into a cave went back into the nether portal but it got stuck loading terrain so I closed Minecraft, but I joined my friends server it keep saying "Unable to join Outdated server!".

Reproduce Steps:

Join a friend's server,

Go into the Nether,

Make two operating portals next to each other,

Enter the right portal,

Go back to the nether,

If stuck, Close Minecraft.