Why am I receiving multiple copies of an email?

[#1]

This morning..  I received a reply to an email I sent.... which is not unusual.... Since then, I have received 12 more replies, all the same... and all with the same "time stamp"... I have informed the sender, and he thinks it may be a "server" problem... either his or mine... not acknowledging receipt, and then triggering another transmission ... or some anti-spam setting..
Either way.. something is not working properly...
Any one got any ideas ? 

[#2]

Are you using PlusNet's email server?

[#3]

yes  
additional info...... I am not, rpt not, getting multiple copies of other emails..... just this one...

[#4]

You have answered your own question, it is the sender's email server up the spout.

[#5]

Hmm...

[#6]

Are you using POP3 or IMAP? If it's POP3, something is preventing the "Dele" command from running at the end of the fetch, which usually happens if the download is somehow incomplete. If you're able to see the offending mail using web-mail, you could just delete it from there.
If you're using IMAP, then I haven't a clue...

[#7]

Are the message ID's in the headers of the received emails the same?
e.g.

Message-ID: <FyVfSabYRRGH-OmCNOFbIg@ismtpd0006p1iad1.sendgrid.net>

[#8]

I am experiencing the same issue however before this last part I had to do many things to whittle it down to the one email or sender that seems to keep pushing emails through. The email headers are exactly the same on the messages. Sometimes they are 10 minutes apart, sometimes hours apart. In one day the message will come through up to 12 times!
I raised a chat online last night and the tech support raised a ticket which has still to be resolved.
It looks very familiar and I am also using POP. Any ideas on this one?

[#9]

So, the message ID's are the same yes?

[#10]

Yes bob, they are identical. I shall post one of them (shortened) with timestamps. The other messages just contain different timestamps but the header info is the same, as is the subject:

Return-path: <***@***p.co.uk>
Envelope-to: ***@madasafish.com
Delivery-date: Wed, 02 Dec 2015 16:24:42 +0000
Received: from [212.159.9.108] (helo=avasin06.plus.net)
	  by inmx16 with esmtp (PlusNet MXCore v2.00) id 1a4ACw-0006zW-IR 
	  for ***@madasafish.com; Wed, 02 Dec 2015 16:24:42 +0000
Received: from mail.***.co.uk ([212.59.78.242])
	by avasin06.plus.net with Plusnet Cloudmark Gateway
	id ogQg1r0035DgRwc01gQitd; Wed, 02 Dec 2015 16:24:42 +0000
Received: from HSD4 (host86-148-218-120.range86-148.btcentralplus.com [86.148.218.120])
	(Authenticated sender: ***)
	by ***.co.uk (Postfix) with ESMTPA id 88F50366053B
	for <***@madasafish.com>; Tue,  1 Dec 2015 14:17:24 +0000 (GMT)
From: "Geoff" <***.co.uk>
To: "'Rob'" <***@madasafish.com>
References: <000401d128ac$82dc0bc0$88942340$@madasafish.com> <000f01d128f3$4255d3a0$c7017ae0$@***.co.uk> <002201d12c41$b4233e40$1c69bac0$@madasafish.com>
In-Reply-To: <002201d12c41$b4233e40$1c69bac0$@madasafish.com>
Date: Tue, 1 Dec 2015 14:17:51 -0000
Message-ID: <01f801d12c43$10390ba0$30ab22e0$@***.co.uk>
X-Mailer: Microsoft Outlook 15.0
X-PN-Virus-Filtered: by PlusNet MXCore (v5.00)
X-PN-Spam-Filtered: by PlusNet MXCore (v5.00)
Subject: RE: Emailing: img735.jpg, img734.jpg, img733.jpg, img732.jpg, img731.jpg, img730.jpg No 69339

[#11]

Return-path: <*@*.co.uk>
Envelope-to: *@madasafish.com
Delivery-date: Wed, 02 Dec 2015 19:25:57 +0000
Received: from [212.159.8.109] (helo=avasin05.plus.net)
	  by inmx19.plus.net with esmtp (PlusNet MXCore v2.00) id 1a4D2L-0002fH-Mn 
	  for rdmacp@madasafish.com; Wed, 02 Dec 2015 19:25:57 +0000
Received: from 243-78-59-212.static.marotori.net ([212.59.78.242])
	by avasin05.plus.net with Plusnet Cloudmark Gateway
	id ojRv1r0095DgRwc01jRx7z; Wed, 02 Dec 2015 19:25:57 +0000
Received: from HSD4 (host86-148-218-120.range86-148.btcentralplus.com [86.148.218.120])
	(Authenticated sender: *.*)
	by mail.***.co.uk (Postfix) with ESMTPA id 88F50366053B
	for <***@madasafish.com>; Tue,  1 Dec 2015 14:17:24 +0000 (GMT)
From: "Geoff" <***@***.co.uk>
To: "'Rob'" <***@madasafish.com>
References: <000401d128ac$82dc0bc0$88942340$@madasafish.com> <000f01d128f3$4255d3a0$c7017ae0$@***.co.uk> <002201d12c41$b4233e40$1c69bac0$@madasafish.com>
In-Reply-To: <002201d12c41$b4233e40$1c69bac0$@madasafish.com>
Date: Tue, 1 Dec 2015 14:17:51 -0000
Message-ID: <01f801d12c43$10390ba0$30ab22e0$@***.co.uk>
Subject: RE: Emailing: img735.jpg, img734.jpg, img733.jpg, img732.jpg, img731.jpg, img730.jpg No 69339

[#12]

I'm guessing the duplicates don't show in Webmail?
The client or servers could be doing something screwy with UIDs, it's difficult to say though. If you are leaving copies of the messages on the server, it would be interesting to see if the problem arises again after deleting the offending message.

[#13]

I have deleted lots of these messages from the clients machine. They are still coming in. You are correct when I logged into the webmail there are no duplicates. Interestingly I have reduced other senders earlier on and received a mail from plusnet staff stating:
"As discussed on the I have removed the email address from the mad as a fish account so you should no longer receive double emails from us."
In fact the webmail only has information from plusnet, not the array of mails on the client PC. Plot thickens.

[#14]

Quote from: rdmacp

I have deleted lots of these messages from the clients machine.

I was suggesting you try and delete the offending message from Webmail rather than the client.

Quote from: rdmacp

"As discussed on the I have removed the email address from the mad as a fish account so you should no longer receive double emails from us."

That's in reference to the emails Plusnet send you.

Quote from: rdmacp

In fact the webmail only has information from plusnet, not the array of mails on the client PC. Plot thickens.

Make sure you're logging into the correct mailbox. The login format for additional mailboxes is <username>+<mailboxname> e.g. to log into the additional mailbox me@username.plus.com, you would enter the username 'username+me' (minus quotes).

[#15]

The account was a madasafish account.
His only account is using username@madasafish.com
I only get the options for server:
Plusnet, Force9, Free-Online and Metronet.
Otherwise I do not follow, sorry Bob..