Net: SMTPUnknownError(无法在我的Rails应用上发送电子邮件时出错3xx (550))

I'm using google for sending emails on my Rails 3.2 app. Most emails functions were working perfectly. Then I did some testing because delayed_job is not working. I got a warning from google that I need to log into the account via the web to unlock it (I sent about 20 emails in a span of 1 hour). Things were back to normal. Now, I am unable to send any emails whatsoever. I have this error message in my server log:I'm using google for sending emails on my Rails