Double-check it's disabled on the website, make sure you saved changes, also try doing /whitelist off in-game, have your friend join, add them to the whitelist, then re-enable it if you wish.

Moved to Skript category. The Help category is for general help, Skript forum for Skript help and so on. 

Check that you:

- Put the .jar file of the plugin into the plugins folder.
- Restart your server afterwards.

I've done all the steps and everything you said but when I go into my server none of the plugins are working or are even there.

I'd recommend installing plugins from official sources such as Bukkit, Spigot, etc. The add-ons panel gets confused with its versions.

Once you've downloaded the .jar file, you can follow these steps to upload it into your server:

1. Go into your server's settings.
2. Go to the File Manager section.
3. Go to your plugins folder.
4. Upload the .jar file of the plugin.
5. Restart your server.