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Authme

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.