# 正确的SMTP配置示例
Mail.defaults do
  delivery_method :smtp, {
    address: 'smtp.example.com',
    port: 587,
    domain: 'yourdomain.com',
    user_name: 'username',
    password: 'password',
    authentication: 'plain',
    enable_starttls_auto: true
  }
end

mail = Mail.new do
  from     'sender@example.com'
  to       'recipient@example.com'
  subject  'Test Email'
  body     'This is a test email'
  # 添加附件时要正确处理
  add_file filename: 'attachment.pdf', content: File.read('/path/to/file.pdf')
end

# 检查邮件格式是否正确
puts mail.to_s

begin
  mail.deliver!
rescue => e
  puts "Error occurred: #{e.message}"
  puts "Backtrace: #{e.backtrace.join("\n")}"
end

Mail.defaults do
  delivery_method :smtp, {
    # ...其他配置...
    logger: Logger.new(STDOUT),
    debug_output: STDOUT
  }
end