Update:
From my Google mail inbox.
This is an automatically generated Delivery Status Notification
THIS IS A WARNING MESSAGE ONLY.
YOU DO NOT NEED TO RESEND YOUR MESSAGE.
Delivery to the following recipient has been delayed:
>> My Google email, I was trying send to mydomain email.
And then, Google gave a guideline.
Message will be retried for 2 more day(s)
Technical details of temporary failure:
The recipient server did not accept our requests to connect. Learn more at
http://support.google.com/mail/bin/answer.py?answer=7720
Learn more