I tried to rewrite the plugin SimpleATM by runesmacher with Vault support. However, the signs aren't working for me. It looks like it works, and the plugin doesn't give any errors on startup or on sign interaction. https://github.com/Tauryuu/ATMEm Thanks in advance.
You didn't put depend: [Vault] in your plugin.yml. Even if that isn't this particular error, then it will help you not get one in the future.