I have a SMTP account by hostgator. It has been working OK for a few years. in the last week all emails sent to gmail accounts are bounced with the following message:

Could not deliver message to the following recipient(s): Failed

Recipient: [email protected] Reason: Remote host said: 421 4.7.0

Senders Guidelines. rx5si6064874pab.151 - gsmtp -- The header and

top 20 lines of the message follows -- Received: from COMPUTERNAME

(cpe-184-152-65-14.nyc.res.rr.com []) by

srv1.MYDOMAIN.com with SMTP; Wed, 30 Dec 2015 20:20:02 +0000

MIME-Version: 1.0 From: [email protected] To:

=?utf-8?Q?=D7=92=D7=9C=D7=99=D7=A7_=D7=95=D7=95=D7=90=D7=9C=D7=A3?= Cc: [email protected] Date: 30 Dec 2015 15:20:00

-0500 Subject: Hello Content-Type: multipart/alternative; boundary=-- boundary_24_202cb606-d866-4f0c-8099-34ebd832de7f

emails sent to other domains (aol,yahoo,etc...) arrive safely. the issue is only to gmail.

i couldnt find much info online. most posts refer to a bulk sending message. but these emails are not bulk. nor is there any reference to bulk in the error response

in the smtp logs from hostgator/smartermail i dont find anything interesting. in fact it seems to be all-ok.

heres a sample

01:46:33 [][57058974] rsp: 220 srv1.MYDOMAIN.com

01:46:33 [][57058974] connected at 1/4/2016 1:46:33 AM

01:46:33 [][57058974] cmd: EHLO COMPUTERNAME

01:46:33 [][57058974] rsp: 250-srv1.MYDOMAIN.com Hello [] 250-SIZE 250-AUTH LOGIN CRAM-MD5 250 OK

01:46:33 [][57058974] cmd: AUTH login aW5mb0BqdWRhaWNhcdhcmUuY29t

01:46:33 [][57058974] rsp: 334 UGFzc3dvcmQ6

01:46:33 [][57058974] rsp: 235 Authentication successful

01:46:33 [][57058974] Authenticated as [email protected]

01:46:33 [][57058974] cmd: MAIL FROM:

01:46:33 [][57058974] rsp: 250 OK Sender ok

01:46:33 [][57058974] cmd: RCPT TO:

01:46:33 [][57058974] rsp: 250 OK Recipient ok

01:46:33 [][57058974] cmd: RCPT TO:

01:46:33 [][57058974] rsp: 250 OK Recipient ok

01:46:33 [][57058974] cmd: DATA

01:46:33 [][57058974] rsp: 354 Start mail input; end with .

01:46:34 [][57058974] rsp: 250 OK

01:46:34 [][57058974] Data transfer succeeded, writing mail to 97641527.eml

01:47:39 [][57058974] cmd: QUIT

01:47:39 [][57058974] rsp: 221 Service closing transmission channel

01:47:39 [][57058974] disconnected at 1/4/2016 1:47:39 AM

the official google page here https://support.google.com/a/answer/3726730?hl=en has several error descriptions. but none match what i am getting "Senders Guidelines"

what can i do about this? where can i look? any links/leads/pointers?


  • hi. thank you. i forgot to note that i already checked that. but the error messages dont match. the closest match is about bulk guidelines, but a)i am not sending bulk, and b) the messages are not identical Jan 4, 2016 at 13:49
  • The beginning of the message is cut off by your local mail system. The complete message is: "Our system has detected an unusual rate of unsolicited mail originating from your IP address. To protect our users from spam, mail sent from your IP address has been temporarily blocked. Review our Bulk Senders Guidelines." Jan 4, 2016 at 16:01
  • hi. thanks. who is cutting off the message? hostgator? smartermail? is there a setting anywhere where i can set to get complete messages? Jan 5, 2016 at 15:21
  • @MichaelHampton can you please elaborate how we can get the full error messages in the log? Jan 14, 2016 at 14:57

1 Answer 1


I'm assuming that your domain is hosted on the Shared environment. In this case, you should contact the service provider i.e. Hostgator. Generally, such errors occur when Google detects some unusual rate of the mail to Gmail from a mail server IP address.

It may be possible that the other domains hosted on the same server have sent the unsolicited mails to Gmail. Here, the tech guy from HostGator can investigate the actual account who sends the mail.

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