If they are in the Sent box in Gmail, that means Google has them and is in charge of delivery. The delay occurs then, after Postman sends the Gmail and before the user receives it.
I can’t imagine why Google would delay sending an email, but it’s possible, if they are having technical problems. It’s not something that should be ongoing.
Yes there are sending limits for Gmail and Google Apps mail.
Are you sending FROM a Gmail address TO a Gmail address? Are you using a custom domain managed by Google Apps?
From a regular gmail address to another regular gmail address. The wordpress is just hosted on an amazon ec2 instance.
The delay also seemed to affect emails sent from gmail to non-gmail addresses.
Inspect the headers of the delayed email and see if there are SPF, DKIM, Spam or Phishing warnings. For Gmail -> Gmail, there shouldn’t be.
No errors there. Here’s the full headers of a delayed e-mail, no warnings, but you can see that the X-Received header near the bottom has a time of 10:28 PDT, but it doesn’t show up as being received until 12:18.
(I’ve changed the names of my servers and addresses, so there shouldn’t be any real identifiable information here)
Delivered-To: [email protected]
Received: by 10.36.51.146 with SMTP id k140csp4076633itk;
Tue, 7 Apr 2015 12:18:20 -0700 (PDT)
X-Received: by 10.140.107.72 with SMTP id g66mr24610220qgf.70.1428434300170;
Tue, 07 Apr 2015 12:18:20 -0700 (PDT)
Return-Path: <[email protected]>
Received: from mail-qk0-x241.google.com (mail-qk0-x241.google.com. [2607:f8b0:400d:c09::241])
by mx.google.com with ESMTPS id i7si8323060qcm.27.2015.04.07.12.18.19
for <[email protected]>
(version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
Tue, 07 Apr 2015 12:18:20 -0700 (PDT)
Received-SPF: pass (google.com: domain of [email protected] designates 2607:f8b0:400d:c09::241 as permitted sender) client-ip=2607:f8b0:400d:c09::241;
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of [email protected] designates 2607:f8b0:400d:c09::241 as permitted sender) [email protected];
dkim=pass [email protected];
dmarc=pass (p=NONE dis=NONE) header.from=gmail.com
Received: by mail-qk0-x241.google.com with SMTP id a135so6360318qkc.1
for <[email protected]>; Tue, 07 Apr 2015 12:18:19 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=gmail.com; s=20120113;
h=message-id:content-type:from:to:subject:date
:content-transfer-encoding:content-disposition:mime-version;
bh=zlBXRQOapUzI/gEBdPsesEjYesFkbV8tzLBkOxfR5Bk=;
b=s5qczZRG/vyDP75w3RgeZSn5TmH/UhpT/7pkhNSR3RNrhCtr2mWzfMFKIaEe2Qxwz0
VRQIE1ehdivDFiX0tNKbq9vRBqRu7r8sEh9pxB7E3kuXUxqRoU7M0lLoqkuv4gJQQgvH
####################################################################
T+6Y+KBN+WmPagniHZAhYbRuofFZJ2uvM1uajIt6frbyIdFkd8EQvNsvo7H+qnjvMeP/
mdAy7nhPCSoep6zOkSlwcMAML+5Y1d3EF6h6vpqfrNQMWfL5/8cFZ+wxQGzA6N2JuS8t
RCJQ==
X-Received: by 10.55.53.72 with SMTP id c69mr33342336qka.67.1428427725440;
Tue, 07 Apr 2015 10:28:45 -0700 (PDT)
Return-Path: <[email protected]>
Received: from localhost (ec2-33-30.compute-1.amazonaws.com. [52.4.43.30])
by mx.google.com with ESMTPSA id 144sm5754934qhx.45.2015.04.07.10.28.44
for <[email protected]>
(version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128);
Tue, 07 Apr 2015 10:28:45 -0700 (PDT)
Message-ID: <[email protected]>
X-Mailer: Postman SMTP 1.5.11 for WordPress (https://ww.wp.xz.cn/plugins/postman-smtp/)
Content-Type: text/html; charset=UTF-8
From: mysite <[email protected]>
To: [email protected]
Subject: Your membership confirmation for mysite.com
Date: Tue, 07 Apr 2015 17:28:45 +0000
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline
MIME-Version: 1.0
<p>Dear newtry,</p><p>Thank you for your membership to mysite.com.=
Your membership account is now active.</p>=0A<p>Below are details about=
your membership account.</p>=0A=0A<p>Account: newtry (to_address@gmai=
l.com)</p>=0A<p>Membership Level: Free User</p>=0A =0A=0A<p>Log in to yo=
ur membership account here: http://mysite.com/login/?redirect_to=3D=
https%3A%2F%2Fmysite.com%2Fmembership-account%2F</p><p>=0A=09Respec=
tfully,<br />=0A=09mysite.com=0A</p><code></code>
The same thing happens if I send two emails from the test script (in the settings) in succession. The first one came through immediately, the second took about an hour and a half.
Ya, you can see that Google held on it to it for two hours. No idea why. Did this happen before you installed this plugin? What if you send from a different Gmail account? Maybe this one has been flagged for something.
