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Automatic alert notification in case of inbound email failures


Article ID: 170809


Updated On:




Your mail sever is not able to accept inbound emails from our servers.  As a result emails are queing up on our server waiting to be accepted by your servers.  It could be due to a number of reasons.  The recipient server may have gone down, run out of space, etc.

You want to know as early as possible of when this has hapened and how many emails are queued up on our side

Generally a 400 seriese error suggesting Recipient is temporarily not available/able to accept new emails.


Any email server.


- Recipient Server has run out of space

- Recipient Server is not reachable

- Recipient Server is experiencing an issue whereby it is not able to accept new emails.


Yes, we can add your recipient domain to a list of domains that we maintain to watch for Domain Queue levels on our side.  You will need to specify/advise us the Threshold, i.e., the maximum number of emails in the queue before you need to be informed.  When the domain queue exceeds the threshold, Technical Support is alerted and one of the members of the team in turn contacts you as early as possible.  

In addition to the threshold, please provide and confirm the following for Authorized Contacts:

  • Names,
  • Phone Number(s), and
  • Email Addresses other than hosted/server by your servers (e.g.,

The above information will be added to Special Instructions under your account to be used at the time we need to contact.  Please make sure this information is a generic and current as possible.


You will need to come up with a number to be used as the Threshold, depending upon your email traffic volume.  For example your threshold will be different if you have a volume of one million emails per day vs 10,000 emails per day.  10K might be good number for the Threshold in case of the former but not in case of the later.   You do not want to wait until emails of an entire day are stuck before you are alerted.

It also depends on the latency you can afford relevant to the critical nature of your business and information need.  The way the alerts works is that we receive an alert every hour based on the number of emails received and not delivered for all domains that are registered with us and that have opted in to be alerted. Therefore, one hour is the minimum.  If your servers stopped receiving/accepting emails one hour, i.e., as soon as the last snapshot was taken, the emails received until the next snapshot will accumulate to get the final number of emails in the queue.  You should see the peak hour of the peak business day for reference.  Say you received 150 emails at the peak hour of the peak day on average, 200 would be a good number for your Threshold.  On average you may have 100 for a day, if you received 2400 emails.  But generally, volume peaks around mid week and around middays.

This is just to give you an idea to help you come up with a good number to avoid unnecessary alerts.  However, we do asses youe email delviery before contacting you, e.g., connection tests etc. are done.

So please make an assessment and advise us of a number for the Threshold and we will be happy to implement the change for you.


After the change is implemented, we will let you know as early as possible, when we notice the queue for your domain exceeding the threshold.


In case you discover an issue on your server side that resulted in the email queues on our side and fixed it, let us know as we can flush the emails in queue for you so you may get them earlier than later.  Otherwise, older emails will take the longest before they get delivered while brand new emails will get delivered right away.  The reason being new emails are tried right way while older emails follow a retry schedule.  The longer an email waits in the queue the later will be tried once the issue is fixed.