Authme

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How to apply resourcepack after login

Open config.yml of ItemsAdder and disable apply-on-join.

resource-pack:
  apply-on-join: false

Open commands.yml of Authme and change onLogin to this:

onLogin:
  apply_pack:
    command: 'iatexture %p'
    executor: CONSOLE

Make sure that there is only one onLogin setting in the configuration file.