Too many concurrent SMTP connections errorMany mail servers are not setup for mass emailing activities The error message in an SMTP conversation of ‘421 Too many concurrent SMTP connections; please try again later.’ can mean a lot of things.
This error message usually means that the connections to the recipient mail server have exceeded the limit. This high traffic to mail servers can sometimes be a temporary problem due to a spike in the connections.

This condition can happen if your mail server is setup to only allow one connection to it per IP and you have Campaign Enterprise sending several campaigns at a time.  To solve this, in the Mail Server Management area, edit the mail server, go to options, and set the concurrent sending to "1 Thread".  In this way Campaign Enterprise will queue up the campaigns and only send one at a time.

I get many questions about why email open rates are so low and if Campaign Enterprise is somewhat to blame. People struggle with trying to understand and explain to their managers why the numbers are lower than you would expect. If people signed up for an email could they at least open the email? Obviously there are reasons, some technical, some with the impact of the email subject or content, but mostly it is just the fickleness of people. For the technical side of things, at Arial Software we have constantly looked for new ways to make sure if an email is opened that we know about it, and tests have shown these numbers are extremely accurate.  Regarding the content of the message, that is the realm of the people creating the email content to capture people's attention but not scare them away.  So, regarding the actual people themselves, we don't have control of that, but what we can show is that even though the open rates seems low, from a standpoint of getting a word out to those interested, email is still the best value out there.

To show your management how you are doing, we have some sources of information for you. ​Some of the greatest sources of information concerning email trends come from email services like Constant Contact and Mail Chimp.  Since they deal with so many industries all over the world there statistics are excellent and revealing.  Below are some links to charts of industry standards for email responses. From what we have found, our client's open rates tend to be higher than average from this chart mainly because our clients have extremely targeted recipients.

Click Here For The Constant Contact Response Rate Chart

Click Here For The Mail Chimp Response Rate Chart

After researching the limitations that exist for sending large batches of emails, here is some of the items I found to apply. The question of how large an email send can be is more of a question of what is practical.  Campaign Enterprise does not set any limitations on the number of emails that can be sent in one batch, but there are Operating System and system resource limitations that are limiting.

To understand the problem, you have to look at what the machine has to do when asked to send 1 million emails in one batch.  When the Campaign Enterprise is first started, it accesses your database using the query defined in the campaign, using a SQL Statement, Table, or Stored procedure.  The result of the query is a list of records which is theoretically a snapshot of a portion of your database based on your criteria.  Since Campaign will have to cycle through this list, maybe for hours depending on your sending speed, this list will have to be stored in memory.  If the entire 1 million record list with all the data associated was loaded into memory, not only would that take a lot of time to transfer this data from the disk into memory, this assumes you have enough memory to handle such a large set of information, so this turns out not to be practical. To balance speed versus resources, what Campaign Enterprise does is it loads into memory just the Unique ID data column of the records that are selected by your query.  In this way, a list of the selected records can now be cycled through, and each record is loaded into memory in turn and the data from that record can be used to send each email out.

Where we have seen the bottlenecks in sending large email batches is in the initial database query. When encountering large batch bottleneck, the SQL Statement being used is not optimized.  Typical problems with a query not being optimized are:

- Columns being used in conditional statements or in table joins are not indexed
- Calculations are being done in the conditional statements

Remember, you can have a perfect SQL Statement or stored procedure, but if you have ONE of these problem elements it will reduce the query time to a crawl.  Many times I have had clients say “this has worked perfectly for years and not it died and nothing has changed”, only to encounter that a column they were using dropped its index or the index was so fragmented it was more of a burden than a help.

Efficiency in Campaign Enterprise starts with efficiency at an Operating System and Database System level.  There is nothing Campaign Enterprise can do to compensate for these outsides systems being deficient.  This is not to say Campaign Enterprise is perfect and its the “other guy”, but more than not it is our experience that the culprit of performance is at the machine/database level.​

Now practically, what do you do when you need to send over 1 million emails?  When datasets get large usually you have to use a different database design strategy.  The key is not how many emails can I send out in one batch, it is how can I sent multiple batches to get all my emails out without exceeding the computer’s limitations.  One strategy to use for sending large batches of emails is to use or create a new column in your database that will know if a record has been sent.  You can do this in Campaign by filtering on this column, and setting the data to “sent” after the email is sent. When you run the campaign again, it will only send to those that have not been sent to yet. There are other ways of accomplishing batching but they all depend on database design strategy.

Campaign Enterprise can connect to any ODBC compliant database, one that complies with Open Database Connectivity requirements. These include, but may not be limited to the following:

• MS Access
• MS SQL Server
• MySQL
• Oracle

There are three steps to go through before making data available to the end user for actually sending the campaign.

• Set up the database connection
• Select the table and and filters
• Assign it to the end user

Set up database connection:

• Determine your database type. The database connection is dependent on what database you intend to use for your email addresses. Go to connectionstrings.com and get the right connection string for your database. You will need to know the version of your database, the permissions used, the IP address and other information as specified by your database administrator. You may also need a username and password depending on how your database is administered.
  
  Example Strings: 
  Access: Standard Security: Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\myFolder\myAccessFile.accdb; Persist Security Info=False;
  
  Access: With Database Password: Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\myFolder\myAccessFile.accdb; Jet OLEDB:Database Password=MyDbPassword;
  
  MS SQL Server: Standard Security: Server=myServerAddress;Database=myDataBase;User Id=myUsername; Password=myPassword;
  
  MS SQL Server: Trusted Connection: Server=myServerAddress;Database=myDataBase;Trusted_Connection=True;
  
  MySQL Standard Security: Server=myServerAddress;Database=myDataBase;Uid=myUsername;Pwd=myPassword;
  
  These are just a few examples. Go to connectionstrings.com to find the string for your database.
• In Campaign, log in as the administrator and click the Administration link.
• Click Database Connection Management
• Click Add New Database Connection
  Name it something readily identifiable, "Main SQL Connection" for example
  Select the database type
  Enter the string, with any variables necessary already filled in.
  
  When you save the string, Campaign will automatically test the connection. You may have to tweak the syntax of your string as prompted to successfully connect.
• If you are in a multi-user environment, make sure you assign the users and groups that have access to this connection.
  

Create External Email List:
You can now create a new external email list, using this connection string. All available connection strings will show in the drop down and you would select the one you need for a particular list.

• Click Email List
  
• Click Add New Email List
• Name the list something readily identifiable "Sales Followup" for example
  
• Select External and click continue
  Select the database connection from the list of available connections
  Select the table, SQL Statement option, Stored procedure or use a filter in the project by selecting "From Campaign"
  Match the columns shown, Bounce, Unsubscribe, ID and Email
  Then save the Email List
• Enter a Bounce SQL statement if you want one.
• Set the permissions for this connection
  

There are other options available for more advanced list configuration should you need it. Please contact technical support for more information. The email list will appear in the campaign to address field for those users with permission to connect to this list.

Though this has been written on before it is always good to review from time to time the subject of bounces.  If you send any quantity of email, whether you use your own mail server or a service, the "quality" of your list is extremely important. If your list has a lot of bad emails then it you could be marked as a "bad" sender and lose reputation with the big-boy mail services.

THE PROBLEM: Returned emails do not have a standard format.  Many initially believe that a "returned" email should be the whole email, which would be wonderful, but usually mail servers in the world either stripe down the email to almost nothing or just send back their own rendition.  Overall, you can not rely on either the headers or the body of the bounced message to be able to reliably identify the original recipient, especially if you want to automate the process. Even if you add your own custom headers, it's likely that the bouncing server will strip them when it sends notification back to you.

The only piece of information that will remain intact in a bounce is the return-path email address because at a minimum the email will need to return to that email address. The only way to automate truly accurate bounce catching is to encode the recipient directly into the return path address itself. This would typically be done by overriding your server's default return path address for each outgoing message, using a unique value per recipient, like bounce-XXXXX@yourcompanydomain.com, where XXXXX is some encoded and/or obfuscated representation of the recipient's email address or some other internal identifier.  This is VERPs, or Variable Envelope Return Path.  Campaign Enterprise v12 uses VERPs to process bounced emails.

Be sure to check out the Campaign Enterprise Version 12 Documentation for more information on how bounce handling is done in Campaign Enterprise v12. 

Dynamic content is one of the key features of Campaign Enterprise. Pulling information out of, and putting information into your database helps you target your email marketing in order to make the most of your contact list. In prior versions of Campaign, dynamic content could get somewhat confusing. Campaign Enterprise version 12 allows for more functionality of the dynamic content features.

Built-In Merge Field
The built-in merge field is similar to that in the past, but adds % signs inside the curly braces { } that were used in the past. The number of percentage signs surrounding the field name differentiate the type of merge being used. Built-in merge fields are those that are provided by the Campaign system to be used in various places in your message, subject line, or write back strings. The basic construct is {%Unique_ID%}.

Examples:
{%UNSUBSCRIBE_URL%}
{%UNIQUE_ID%}
{%CAMPAIGN_NAME%}
{%CAMPAIGN_ID%}
{%VIEW_AS_WEBPAGE_URL%}

Basic Merge Field
The basic merge field, that pulls information from the database to which your campaign is connected, uses two percentage signs inside the curly braces. Using the basic merge field, you can personalize your message to each individual record in your list. For example, you can include the {%%FirstName%%} field in your subject line, or salutation line in the message body, it will pull that data from the table and insert it where the merge field is located. The basic construct for the basic merge is {%%FieldName%%}. Please note that the field name comes from your table, and will need to be changed and modified accordingly.

Merge Functions
The newest merge functions can also be considered message content programming. Using these functions you can modify the message, based on individual data stored in your table, as the message is generated. The delimiters for merge functions contain three percentage signs inside the curly braces. A basic example shows a replacement for a blank first name field, to a default value.
Dear {%%%=NZ(Firstname,"Valued Customer")%%%}. In this instance, if the Firstname field specified happens to be blank, the term Valued Customer will be used in its place.

There are a number of basic functions available, and great flexibility to modify and create more.
NZ <column name>,<defalut text>
FormatNumber <column name>,<format string>
FormatDateTime(<ColumnName> or SYSTEM_TIME,<FormatString>)
FormatCurrency(<ColumnName>)
Select(<ColumnName>,<MatchValue1>,<ReplaceValue1>,<MatchValue2>,<ReplaceValue2>,...)
If(<ColumnName>{conditional}<Constant>,<TrueValue>,<FalseValue>)
IncludeTextFromURL(<URL>)
IncludeTextFromFile(<FilePath>)

More information on the available string can be found in the Campaign Enterprise 12 documentation, starting at page 54.

Start making the most out of the information you collect, to create highly targeted and desirable emails that get responses.

Link tracking is an important part of any email marketing campaign. With Campaign Enterprise 12, this feature is much easier to configure than in any previous version of our program. The first step in tracking links is to build them in your html message. You create hyperlinks, just as you would for a web page, simply highlight the text you want to turn into a link, and click the link icon in the tool bar.

You can have as many links in your email as you want. You can also apply link images and image maps if you wish. Once you have your message complete, simply click the Click Tracking button on the message page.

Click Extract Clicks from Message at the top of the page, and Campaign will search the message for links.

If you decide not to track a particular link, simply un-check the box. You can use third party tracking codes, like Google AdWords, by pasting their tracking code in the Tracking Code box.

Now that Campaign works with IIS, you no longer have the tricky step of setting configuring alternate ports. The public web page you set up when installing campaign is used to process links and even host the images in your message.

Using a standard email template for your mass emails helps you keep your messages clear, concise and consistent. With Campaign Enterprise 12, you can now upload your email templates into the interface and make them available for other users.

To add a template, log into campaign as an administrative user.

1. Go to the Administration area and click on Manage Email Templates.
2. Click Add New Email Template
3. Name the Template, use something that easily identifies the template's purpose, like "Newsletter Template"
4. Build your template or paste the HTML code into the editor
5. Click Save

You will see all available templates listed here. The template can be edited at any time. Changing the template will not change anything in the campaigns that have previously pulled the template down for use. Once pulled into a campaign, the template can be modified to suit your purposes.