Added: 09/22/2013 | Updated: 7 Months Ago
Email Delivery Overview
There are many things that can affect email delivery. Also, many items can work together to cause an email to not deliver. There are four primary causes:
- Spam Filter: This can be either the email going into the spam folder, or not being delivered at all.
- Software Issue: This can either be an issue with the code, or an issue with the settings (exa: Advanced Features)
- Email Que: The email might be in an email que waiting to be sent that prevent the email you are testing with from being sent. If your email que is full with 10,000s of emails there could be a long delay (hours or even days). If there are 100,000's of emails in your que, and your throttle is not configured correctly, and you are actively sending emails, then your que may continue to back up further and further and none of the emails are sent until a change is made.
- Blocked By Blacklist: This happens when either the IP or the domain name associated with your system has been added to a blacklist.
What Web Marketing Tool Can Do
For us to assist with email delivery related request you will need to open a support request no matter the reason for the request. If it turns out to be a blacklist issue or bug then you will not be charged for time spent. For all other issues you will be charged. In order to save us time, potentially saving you money, we need to know a specific email address that is having the issue. Otherwise, either we may be completely stuck, or we may need to go through checking multiple contacts to see if any of them have the issue, and most often we are unable to quickly find one and end up wasting time, costing you money.How To Help Us:
Below we describe many things you can do. First, check if a software issue exists or email que problem exists by checking if a statistic for the email exists. If no statistic exists, then it is one of those 2 problems and follow the instructions below to research further. If it isn't one of those issues, then send us the email address and time of the test email that you sent that didn't deliver. Also, we may need more information. Oddly enough, most the time we ask for a specific piece of information we don't receive it, and you can help us out by giving us the specific details we ask for rather than repeating that the problem still exists. With email related issues, most credits are spent in back and forth negotiations to get the details we need. Very often the reason we need these details is we are searching HUGE reports for a specific piece of information, so being very specific is very helpful.
Email Delivery Issues
Email delivery is a huge subject, as there are many things that impact it. The largest factor with email delivery rates is your reputation. Your reputation is based off percentage of emails that you send that are marked as being spam by the receiver.
When an ESP (Email Service Provide. Exa: Yahoo, GMail, Comcast, etc) receives your email, they make a decision if they will deliver the email to the inbox, or deliver it to the spam folder, or completely block the email. Each ESP has it's own criteria it uses to determine how they treat your email. These rules change between ESPs and most ESPs use many items that they look at to determine an overall score and based off your score they decide what to do with your email. Although each ESP decides what criteria they use, and how important they see it, below are some common criteria that most ESPs look at:
- Domain Name Reputation: Your domain name has it's own reputation based off the emails that you have sent in the past. A negative reputation can cause your emails to be more likely to go into a spam folder. A very bad reputation can even cause your email to be completely blocked.
- IP Reputation: The IP that your site lives on is nearly always used as a factor when determining email delivery. What this means, is that if many sites share the same IP, then if one site sharing the IP is sending spam, then it can negatively affect the email delivery of other sites sharing the IP. From our experience, your domain reputation is more important than the IP reputation, but having a fresh IP with no reputation is worst than having a fresh domain with no reputation.
- Content of Email: The content of the email is a huge factor that ESPs look at. There are many items they look at including the amount of content, the amount of images, the sites being linked, the words used, and much more.
- Email Structure: The way your email is structured, including if you use DKIM, rDNS is setup, and other factors are looked at by ESPs.
Your reputation is a big part of email delivery. Your reputation is like a credit score, based off previous actions. When you start off you have no reputation, which similar to a credit score, can in some cases be worst than a bad reputation. Also, like a credit score, it takes time (weeks/months) to build your reputation. If you send emails that are perceived as spam by the recipients, and then they click a button inside of the email marking it as spam, or delete the email without opening it, it can affect your reputation. The main site to use to monitor your reputation is Sender Score
. Some things you can do to improve your reputation include:
- Send emails that are seen as useful, and not strictly sending
- Do not send emails too frequently. Daily, or even weekly emails that are strictly promoting your product, without providing useful information are very likely to be seen as spam.
- Do not send emails to sporadically. What I mean, is don't not send an email for several months, and then all of a sudden start sending daily emails.
- Do not import contacts that are purchased from a source that is not reputable. Typically, it costs around $1 for a good quality lead. If you are getting contacts for pennies on the dollar, or even less, you can be confident that these contacts are low quality and that emailing them from your system will cause your reputation to become worst.
All the systems we host use a shared IP except for sites that are on a dedicated server, or sites that have SSL installed. If you are on a shared IP, it means you share the IP reputation with other sites using the same IP. The way we control spam is by charging email overage rates for more than 10,000 emails. For our shared IPs we have 3 types of shared IPs, each with a different overage rate. This means, that we have IPs where it costs more if you send bulk emails. By doing this we hope to allow clients to have better email delivery by paying extra per an email to know that everyone else is also paying extra, thus encouraging systems to send higher quality emails with those higher priced IPs. You can request for us to add you to a higher priced IP.
Content of Email
There are many items related to the content of the email that can affect delivery. Below are several items to consider:
- Words Used: The words you use inside of an email can affect delivery rates. For example, using the word free may cause your email to be less likely to deliver to some ESPs. Using a specific word is very unlikely to get you blocked by itself, but when combined with other factors, like other content, reputation, email structure, etc., then they may add up to a point where the words you use are the "straw that breaks the camel's back" causing your email to not be delivered.
- Sites Linked To: By linking to sites that are seen as "spam" sites or sites reported for other malicious activity can cause your emails to be less likely to reach the inbox.
- Too Many Images: If your email has very little plain text, and instead is mostly images (or text inside of images) it can cause your email to be les likely to deliver.
- Other Items: There are many other items that can also cause problems, like using too many symbols, like too many $$ signs, or using all caps, or many other similar criteria that some ESPs watch for. Please read through the email delivery resources below as we link to many sites with additional valuable information about email delivery.
The structure of the email being sent can affect delivery rates. The structure includes having rDNS, DKIM, SPF, and other similar items setup. For our shared IPs we setup everything. For a dedicated server we setup everything for the first IP (a dedicated server includes many IPs). For a site that we install SSL for we do not setup DKIM or rDNS automatically. If you are using a dedicated server or have SSL for your site you can request for us to add rDNS or DKIM for your site as a support request. Click here to learn more about DKIM
Below are several links to sites with additional information on what can be done to improve email delivery:http://www.constantcontact.com/learning-center/hints-tips/volume8-issue6.jsphttp://www.the-dma.org/antispam/EmailBPFINAL.pdfhttp://www.returnpath.com/wp-content/uploads/resource/email-marketing/Return-Path-Email-Marketing-Guide-9_12.pdfWays To Improve Email Delivery Rates
- Establish a good email reputation by not sending out emails that could be considered spam and by not sending emails too frequently. The more useful an email is, the better.
- Have your members follow the whitelist instructions to whitelist your domain name. Possibly provide a reward for them doing it if possible.
- Ask your members to open each email they receive, and not delete without opening, as it is suspected that many ESP's (Email Service Providers) monitor these actions.
- Do not send emails which only contain images, but no (or very little) text. This is seen as being a sign of spam by many ESP's.
- Limit how often OR how many emails your members can send.
We have reports where we can monitor complaint rates for your members. We have not yet made these reports visible to our clients, but if you put in a request, we can send you a copy of the report so you can contact/delete members that have higher complaint rates.Shared vs Dedicated IPShared IP
Unless you have a dedicated/cloud server OR you have purchased an SSL certificate then you are on a shared IP. If you are not sure about sentence one, and host with us, then you are on a shared IP. What this means, is your emails are being sent from the same IP other sites use to send emails. This means that one person in the group can affect email delivery rates for others. However, we have found that the impact from other sites is relatively small and that the reputation from your domain has a much larger impact than the reputation of your IP. Also, we charge all sites we host overage rates to prevent them from spamming. We have found that sending more emails is actually better than sending too few. Also, sending emails consistently everyday is important as if you have big fluctuations in the amount of emails being sent it often seen as being a sign of spam. We believe that it is because of this factor that most sites actually get better delivery rates on our shared IP than they do when put on their own dedicated IP (even when they have higher email standards than other sites). Our advise is to not consider a dedicated IP unless your site is sending enough volume (50,000+ emails a month).Dedicated IP
If your site is on a dedicated IP because you purchased an SSL certificate then there are several items we can do to help with delivery rates. If your site is on a dedicated/cloud server then this is already done for your primary domain when we install your server. What can be done for other dedicated IP sites is we can apply for Feedback Loops for your site and we can setup DKIM. Feedback loops allows us to better identify spam issues. DKIM is a form of email authentication which helps ESP's know that the email sent came from you and is not someone spoofing your domain.Return Path
For sites with a dedicated IP, after 3 months of email history, you can purchase email certification from ReturnPath.com
An actual bug in the software itself is rare, more often there is either an issue with a setting under advanced features, or a problem with custom code that was created for you.
- How Do I Know?: The way you can tell if there is a software issue causing the email to not be sent is to check if email statistics exist saying that the email was sent. You can see email statistics at the bottom of the statistics page for a specific contact. When you click the red statistics icon the contacts page it will show the date/time the email was sent, and the subject of the email. If you see such an email statistic, then there is 99+% chance that there IS NOT a software issue causing the email not to deliver.
Broadcast emails and follow up emails are not sent instantly. Instead they are added to a que and sent in the order they were added. The default setting is to send 20 emails each minute from the que. So, for example, if you send a broadcast email to 10,000 contacts, and the que is set to 20, then it will take over 8 hours to send all of the emails. You can modify the que amount under advanced features, but setting it too high may cause multiple emails to be sent (see below). Also, by having it lower you may be able to improve delivery to some ESPs because you are not sending them a bunch of the same emails at once, so having a lower throttle rate is often better. However, if you are sending 10,000s of emails a day then you need to have the throttle set high enough so that it can keep up and doesn't get backed up. In the WMT client admin, under the page for your site, under the site tab, under the tools tab, there is a link you can click to see how many emails are currently in your que, and another link to delete all emails from your que if you want to empty out the que. If an email statistic exists for the email you had delivery issues with, then the problem is not that it is still in the email que.
Blocked By Blacklist
Your email may be blocked when either the IP or domain associated with your system has been added to a blacklist. ESPs (Email Service Providers) may choose to monitor a specific blacklist, multiple blacklists, or even have their own blacklist, and if either your email or IP is on this blacklist then they may either block your email or cause it to go into spam.
- How Do I Know?: When an email is blocked because of a blacklist, or even for other similar reasons, the ESP almost always responds that it is being blocked in the SMTP log. In newer systems (4.22+) under the emailssent log you can see details of what the SMTP response was from the ESP. In older systems, and some other cases, we will need to search the log for you. For us to search the log we need to know the recipients email and the approximate time that the email was sent to them. You will need to do this as a support request, and if in fact it is being blocked we will not charge you for time spent and will request to have the block removed. Also, you can check blacklist sites, or tools that search multiple blacklists (click here to view such a tool) to see if you are listed.
- Removing Blocks: Anyone can apply to have a blacklist block removed, however, typically it is best for us to do it and it is something we do for free. We need to find the SMTP response as described above, and then we can use that to request that the block is removed. Typically it takes 1-4 days for a block to be removed. It is not guaranteed that a block removal request will be honored, but nearly always it is honored.
Other Delivery Issues
- Multiple Emails Sent: If a member receives the same email over and over, so far every time we've seen this it is because the throttle is set to a high value. When the throttle is set to a value higher than what it is able to complete within 1 minute then it is possible that it will send the same email multiple times. Based off expirements, 500 is too high. 100 we've found to be ok. Typically we advise the lowest possible number you can choose.
Questions And AnswersI'm concerned about blacklisting of your auto-responders IP,what are you doing to provent this from happening? How or what is the deliver ability of the emails that are sent out by your auto responder?
How good is your email deliverability for hosted system?
With a dedicated IP what can I do to improve email delivery rates?