Google Mail Rejects Emails Sent From My Server

I sent a message using to and I get this message bounce back:

This is the mail system at host server1.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

: host[]
said: 550-5.7.1 [] The IP you're using to send mail is not
authorized to 550-5.7.1 send email directly to our servers. Please use the
SMTP relay at your 550-5.7.1 service provider instead. Learn more at
550 5.7.1
b6si5975365vdw.127 (in reply to end of DATA command)

Please let me know how I can fix this.


i have same problem ive googles and tryed loads but nothing works it sucks and dont seem to get any help here