The following login action will produce "ERR_ACTION_ACCESS_UNDEFINED" exception (see callstack below). The original rejection reason is lost.

@Module({name: 'auth', namespaced: true})
export default class AuthModule extends VuexModule {

@Action
  async login(payload: any): Promise<any> {
     return Promise.reject('login failed');
  }
}

ERR_ACTION_ACCESS_UNDEFINED: Are you trying to access this.someMutation() or this.someGetter inside an @action?
That works only in dynamic modules.
If not dynamic use this.context.commit("mutationName", payload) and this.context.getters["getterName"]
Error: Could not perform action login
at Store.eval (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:311:33)
at step (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:96:23)
at Object.eval [as throw] (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:77:53)
at rejected (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:68:65)
undefined