Emails to all Gmail Accounts bounce back (Error 550-5.7.1)

tibetors

Registered
Sep 10, 2019
3
0
1
Istanbul Turkey
cPanel Access Level
Root Administrator
Our mail server uses Cpanel, and we have been able to send emails to Gmail accounts until July 8th, 2022. Since July 8, our emails to all Gmail accounts, whether personal or business email accounts, have been bouncing back with the same error message:

host gmail-smtp-in.l.google.com [173.194.76.27]
SMTP error from remote mail server after end of data:
550-5.7.1 [31.210.79.7 12] Our system has detected that this message is
550-5.7.1 likely unsolicited mail. To reduce the amount of spam sent to Gmail,
550-5.7.1 this message has been blocked. Please visit
550-5.7.1 Why has Gmail blocked my messages? - Gmail Help
550 5.7.1 for more information. e13-20020a5d6d0d000000b0021d1a34e643si8109664wrq.1029 - gsmtp

All emails to other email servers work well, except for Gmail. We have valid DKIM, SPF and DMARC records and are below:

SPF:

v=spf1 +a +mx +ip4:31.210.79.7 ~all

DKIM:

v=DKIM1;
k=rsa;
p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDXnyVc+eL+tgXpawFuKH+zNDBIAFk8qsX/R/YA2uMZDTTjZqhWDqat3k9dmqYRf141iknu2ppni9i2tkrAZv4PqIWp8lpNQNNT0V6C1zNMfssX5e3+ub1hjFUXPdYI0bqMNyGrRFI4pvAIKOZa89Lw2DP0FbVFhaIZuLkRk08JXwIDAQAB

DMARC:

v=DMARC1; p=none

PTR is valid. We have not changed any setting recently. We are not listed on any SPAM lists.

What we have done until now:

  • We have sent requests to Gmail using their form to unblock our mail server.
  • We have activated our Gmail Postmaster account, but we cannot see any activity on the account because it is new and there are currently no exchanges between our mail server and Gmail.
Any help to resolve the issue would be appreciated because we have not been able to email any Gmail accounts and we cannot figure out why!
 
Last edited by a moderator:

cPRex

Jurassic Moderator
Staff member
Oct 19, 2014
11,718
1,862
363
cPanel Access Level
Root Administrator
Hey there! Unfortunately this is going to be up to Gmail to resolve as it doesn't like you have already done everything necessary on the server side (SPF, additional verification, etc.) to get the email up to their standards. I would wait and see what they say and then go from there, but if you're blocked there isn't anything you can do on the server-side to resolve that.
 

mtindor

Well-Known Member
Sep 14, 2004
1,452
110
193
inside a catfish
cPanel Access Level
Root Administrator
Our mail server uses Cpanel, and we have been able to send emails to Gmail accounts until July 8th, 2022. Since July 8, our emails to all Gmail accounts, whether personal or business email accounts, have been bouncing back with the same error message:

host gmail-smtp-in.l.google.com [173.194.76.27]
SMTP error from remote mail server after end of data:
550-5.7.1 [31.210.79.7 12] Our system has detected that this message is
550-5.7.1 likely unsolicited mail. To reduce the amount of spam sent to Gmail,
550-5.7.1 this message has been blocked. Please visit
550-5.7.1 Why has Gmail blocked my messages? - Gmail Help
550 5.7.1 for more information. e13-20020a5d6d0d000000b0021d1a34e643si8109664wrq.1029 - gsmtp

All emails to other email servers work well, except for Gmail. We have valid DKIM, SPF and DMARC records and are below:

SPF:

v=spf1 +a +mx +ip4:31.210.79.7 ~all

DKIM:

v=DKIM1;
k=rsa;
p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDXnyVc+eL+tgXpawFuKH+zNDBIAFk8qsX/R/YA2uMZDTTjZqhWDqat3k9dmqYRf141iknu2ppni9i2tkrAZv4PqIWp8lpNQNNT0V6C1zNMfssX5e3+ub1hjFUXPdYI0bqMNyGrRFI4pvAIKOZa89Lw2DP0FbVFhaIZuLkRk08JXwIDAQAB

DMARC:

v=DMARC1; p=none

PTR is valid. We have not changed any setting recently. We are not listed on any SPAM lists.

What we have done until now:

  • We have sent requests to Gmail using their form to unblock our mail server.
  • We have activated our Gmail Postmaster account, but we cannot see any activity on the account because it is new and there are currently no exchanges between our mail server and Gmail.
Any help to resolve the issue would be appreciated because we have not been able to email any Gmail accounts and we cannot figure out why!
If the email in question came was not SENT by one of your users but rather FORWARDED from one of your users' accounts to Gmail, that's probably the issue. When a (legitimate) email is forwarded, it is much much more prone to being tagged/blocked than it would be if it were an email SENT from the user themselves, assuming that the sending domain has proper SPF / DKIM / DMARC.

Of course, you will also want to make sure that you have SRS (Sender Rewriting Scheme) enabled in WHM to help with forwarded emails to more successfully be delivered.

m
 

tibetors

Registered
Sep 10, 2019
3
0
1
Istanbul Turkey
cPanel Access Level
Root Administrator
If the email in question came was not SENT by one of your users but rather FORWARDED from one of your users' accounts to Gmail, that's probably the issue. When a (legitimate) email is forwarded, it is much much more prone to being tagged/blocked than it would be if it were an email SENT from the user themselves, assuming that the sending domain has proper SPF / DKIM / DMARC.

Of course, you will also want to make sure that you have SRS (Sender Rewriting Scheme) enabled in WHM to help with forwarded emails to more successfully be delivered.

m
Hi mtindor,

Thanks a lot for your input. But the email in question was sent.