Bukkit

I installed LobbyAPI quite a while ago. The plugin worked fine on my server for a good few days. Now it is preventing players from connecting to my server. 

Hi superdtk7,

How exactly do you know that is its lobbyAPI preventing them from joining? If you remove all other plugins from the server except for LobbyAPI, does the problem still occur?

Turns out lobbyapi was too much for my server. I upgraded, but know I have another problem. The end portal teleports ever player to the nether. Is this a lobbyapi issue or should I look for other plugins preventing players from entering the nether?

Depends. Check the config.yml for the world you are in, and make sure that the "END" and "NETHER" sections link to the correct nether/ends for that world.

If they are linking correctly, try removing all other plugins from your server and see if that fixes the problem. If so, there was most likely a conflict with another plugin.