我花了几天时间在这上面，大约100个小时，但不能得到修复。
下面是我的设置（使用Rails 4.2.8）

class CustomJob < ActiveJob::Base
  def perform(*args)
    filename = args.first
    data = File.read(filename)
    #  process that data
  end
end

当我运行Delayed::Job.enqueue CustomJob.new('filename')时，我得到了主题中提到的错误。作业已创建并添加到数据库，但错误消息为“作业失败...”
我有这样的台词：

require 'custom_job'

包括script/delayed_job.rb、config/initializers/delayed_jobs.rb、config/initializers/custom_job.rb和我调用作业的文件。
我还补充了这一点：config.autoload_paths+=Dir[Rails.root.join('app','jobs')] config.active_job.queue_adapter = :delayed_job到config/application.rb文件
还有这个

config.threadsafe! unless defined? ($rails_rake_task) && $rails_rake_task

我也在每次更改后重新启动服务器。并使用以下命令验证delayed_job是否正在运行：

dir$ RAILS_ENV=development script/delayed_job status
delayed_job: running [pid 64503]

来源：

• delayed_job fails jobs when running as a daemon. Runs fine when using rake jobs:work
• DelayedJob: "Job failed to load: uninitialized constant Syck::Syck"
• Rails Custom Delayed Job - uninitialized constant
• model classes not loading in Delayed Job when using threadsafe