Missing Emails. Where are they going and how do I fix it?!?
July 25, 2011 10:08 AM   Subscribe

1% or 2% of all emails sent to me never arrive. What is going on and how do I fix it! (It has nothing to do with my spam filters or folder.) Help!

I have my own domain name for my small business. It has been hosted at aplus.net for about ten years. About four months ago, a few of my customers and suppliers started complaining that they were sending me emails that I just never received. At the time I was using Thunderbird. At first I thought the problem was with Aplus. I called tech support and they swore the problem was Thunderbird.

Keep in mind I was receiving about 98%, 99% of all email. But about once or twice a day, something important would never show up. I checked my filters, my spam files, my trash. These lost emails were no where to be found. (I'd learn about it from follow-up emails or angry phone calls.)

Since I couldn't figure out any way to understand if the problem was Thunderbird or Aplus, I decided to switch to Zoho.com for email. I switched all of my MX Records in my control panel as per zoho's instructions (see below.) I am not that tech-savvy, but I figured this both moved me off Thunderbird and -- with my MX records pointing to zoho -- bypassed aplus in case the problem was them.

For about the first two weeks of the move to zoho, no reports of missing emails, but now it is happening again. I've had two customers complain of emails they sent that never arrived in the last four days. Nothing in the spam folder, no filters, no explanation. The emails from my clients saying, "Hey, why haven't you responded to email #1" have arrived, so it doesn't seem to be anything related to the particular sender.

Help! Do I need to switch hosts? Did switching to zoho and changing my mx records not bypass aplus on the chance the problem is them? What could the problem be? How do I fix this before I miss something critical that cripples my business?!

I followed these directions exactly...

Zoho instructions:

MX Records are resource records required to route mails across to the mail servers that receives emails for your domains. To successfully receive mails, the MX information has to be changed in the control panel of your domain.
Priority Mail Server
10 mx.zohomail.com
20 mx2.zohomail.com

Usually, the MX changes gets effected only after an hour or so.
posted by tangyraspberry to Computers & Internet (10 answers total) 1 user marked this as a favorite
Your provider may use some kind of white, black or gray listing. If those emails are resend, do they arrive?

I had once problems too when I switched to an Asian hosting company. Bad move, very bad move.

Now I I use gmail for my emails with my own domain and I am very happy with it. Unfortunately, they reduced the free accounts down to 10. You could have 50 before.
posted by yoyo_nyc at 10:13 AM on July 25, 2011

Troubleshooting advice:

determine a concrete example of a message that was sent but not received - up to and including the exact time/date/subject of the sent message.

Approach your own technical support (zoho?) first, and ask them to verify in the mail logs whether they see any delivery attempt for message x from sender y at time z in the logs. If they do, great, there should be your answer (either it was delivered successfully to you, or more likely, there's an SMTP error code rejection in the logs).

Assuming your own support people can find neither, have your sender approach their support people to do the exact same thing ("Hi, I sent x message to y on z, but they never received it. they've verified that the incoming mail server has no record of delivery being attempted, can you please examine the outgoing mail server logs for any trace of this message / reason why it was not delivered? Thanks.")

hope this helps.
posted by namewithoutwords at 10:22 AM on July 25, 2011 [3 favorites]

Are any of the the customers who are sending to you receiving any sort of bounce back message?
posted by dgeiser13 at 10:37 AM on July 25, 2011 [1 favorite]

I'm betting it's greylisting. I've had too many providers thinking they were doing me or companies a favor by using it, when many sending servers still will not responding properly to greylisting.

But the other thing that I've had problems with is rampant misaddressing. For one of the organizations I manage, we have two dozen different domain names, all variations of the main one. We get legitimate email at *all* of them at some point in the course of the year. So, are you sure that your address isn't an easy one to make a mistake with? Do you have all the possible variants pointing in the right place? Both before and after the @ symbol?
posted by Mo Nickels at 11:41 AM on July 25, 2011

No one sending me anything is getting any sort of bounce back message.

What is gretlisting and how do I fix it?

Thanks for the help everyone!
posted by tangyraspberry at 12:33 PM on July 25, 2011

OK, I am reading about greylisting on wikipedia and it seems likely. I am unclear if it is happening at my host (aplus.net) or zoho. If at aplus, why doesn't changing the mx records go around the web host?
posted by tangyraspberry at 12:40 PM on July 25, 2011

Nthing greylisting. The mail just gets dropped like a bad packet; there's no bounce and no error. Your mail server should have logs, though.
posted by goblinbox at 3:06 PM on July 25, 2011

The mail just gets dropped like a bad packet; there's no bounce and no error.

This is not true. The greylisting (receiving) mail server rejects the SMTP transaction with a 4xx error code, which is a soft error, meaning that the sending mail server should retry sending at a later time. This turns out to be an incredibly effective anti-spam technique, as most spammers/spamming software do not employ robust/full-fledged SMTP processes and instead of trying again will just move on to the next target address.

However, with some legitimate-yet-poorly-configured (read: brain damaged) servers, it can sometimes cause problems. In the case where you have a business need to interact with the rest of the world, it is probably safer to have your host (zoho) disable any greylisting for your account and just deal with the extra spam (again, this makes the as-yet-unproven assumption that greylisting is the culprit.)
posted by namewithoutwords at 4:27 PM on July 25, 2011 [1 favorite]

Do what namewithoutwords said. Mail systems are (historically) designed to be reliable; they log enough information to be able to locate the problem pretty precisely, if you can get the relevant sysadmins to actually look at the logs. If you can't get your host's admins to work on this, move to a new host.

Also, start collecting details of the lost messages: who sent them and when. See if a pattern emerges. The sysadmins will also be more willing and able to look into things if you can give them a detailed list of missing messages.

This doesn't really sound like a graylisting problem to me, but who knows what braindamage lurks in the mail systems of the internet?
posted by hattifattener at 9:24 PM on July 25, 2011

I use Tuffmail for my domains, and they have superb user-acessible logs for these sorts of things, as well as auto-whitelisting for addresses that you've sent mail to.
posted by trevyn at 10:39 PM on July 25, 2011

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