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I have my own VPS where a site is running (control panel: directadmin). When I send mails, some are being delivered (hotmail, gmail, ,...), others are not (, others are delivered after being greylisted (


What could be the cause of this? Is the problem Sender-Side or Receiver-Side? case 1: (delivered)

2012-06-20 15:02:03 1ShKXr-0005Sc-7g <= U=apache P=local S=1319 T="Password reset" from <> for
2012-06-20 15:02:03 1ShKXr-0005Sc-7g [2a00:1450:8005::1b] Network is unreachable
2012-06-20 15:02:03 1ShKXr-0005Sc-7g => F=<> R=lookuphost T=remote_smtp S=1355 [] X=TLSv1:RC4-SHA:128 C="250 2.0.0 OK 1340196103 cp4si34336466wib.14"
2012-06-20 15:02:03 1ShKXr-0005Sc-7g Completed

case 2: (not being delivered)

2012-06-21 09:57:14 1ShcGQ-0007No-5H <= H=localhost ([])       [] P=esmtpa S=740 id=85b1652a3cd4229f2164916bbb5f9023.squirrel@ T="hey" from <> for
2012-06-21 09:57:14 1ShcGQ-0007No-5H ** F=<> R=virtual_aliases:
2012-06-21 09:57:14 1ShcGQ-0007Nt-7Z <= <> R=1ShcGQ-0007No-5H U=mail P=local S=1546 T="Mail delivery failed: returning message to sender" from <> for
2012-06-21 09:57:14 1ShcGQ-0007No-5H Completed
2012-06-21 09:57:14 1ShcGQ-0007Nt-7Z => info <> F=<> R=virtual_user T=virtual_localdelivery S=1643
2012-06-21 09:57:14 1ShcGQ-0007Nt-7Z Completed

case 3: (greylisted)

2012-06-21 15:29:02 1ShhRW-000862-BV <= H=localhost ([]) [] P=esmtpa S=782 id=66feba965b2c2abc2c41b0ee22925df5.squirrel@ T="testmail squirrel" from <> for
2012-06-21 15:29:02 1ShhRW-000862-BV SMTP error from remote mail server after RCPT TO:<>: host []: 450 4.7.1 <>: Recipient address rejected: Greylisted for 5 minutes
2012-06-21 15:29:02 1ShhRW-000862-BV == R=lookuphost T=remote_smtp defer (-44): SMTP error from remote mail server after RCPT TO:<>: host []: 450 4.7.1 <>: Recipient address rejected: Greylisted for 5 minutes

Notice that the "from" in case1 differs in case2: or

Thanks for your time!

share|improve this question

closed as off-topic by HopelessN00b Apr 3 '15 at 18:16

  • This question does not appear to be about server, networking, or related infrastructure administration within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

This appears to be server side on the recipients domain.

I would contact their postmaster and see if you can have your domain white-listed. That way any mail you send would be delivered without going through the same SMTP spam checks that happen with other mail servers.

They could have more than one mail server load balanced that you are hitting spam rules for. Thus causing you to not be able to deliver. We are very protective of our mail server IPs just because it can take a very long time to generate a positive reputation on the Net for sending email and no time to ruin it.

Another option would be set up your mail server to relay all email through a larger email provider who typically are white listed by default and/or have a staff to manage issues of this sort.

Best of luck!

share|improve this answer
I don't think contacting their postmaster is an option because I will be emailing all my app's users so it will be impossible to ask all of their permission. I will read into your second option. – Tom Broucke Jun 21 '12 at 14:58
@TomBroucke If you intend to use email to communicate with users en masse you need to either either accept line loss or be willing to talk to postmasters at the remote sites. Relaying through a third party provider can get expensive in a hurry with volume fees. Also remember the SMTP Mantra: Email is not a reliable message delivery service - Just because it usually gets there doesn't mean there are any guarantees that it will work this time. Delivery of any message can fail for any reason, or no reason at all, and once our server hands it off there's very little I can do to help you. – voretaq7 Jun 21 '12 at 15:10
It looks like the greylisting just solved itself. But the problem of not receiving emails is still an issue. Maybe it is noteworthy to say that (not delivered) and (greylisted at first) both are hosted on Kind of strange that same host would refuse my emails for one domain and not for the other? – Tom Broucke Jun 21 '12 at 15:11
@voretaq7 Yes I know that line loss is inevitable, but I wouldn't want to launch a webapplication where I can't even reset my own password etc.. – Tom Broucke Jun 21 '12 at 15:14
Administering a mail server that is sending email has become an art-form. Since spam has become so prevalent and spammers are very crafty a lot of mail servers have moved to a deny at the smallest sign of an attack. If you are interested you can read up on running a bulk mail server to get an idea how it all works. – J Baron Jun 21 '12 at 17:33

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