Sending Mail through 3rd Party SMTP Services

Premium Service

Additional fees apply for using a 3rd Party SMTP service.


In addition to sending email through Lead Liaison's professional-grade email marketing infrastructure, Lead Liaison also supports sending email through approved 3rd party SMTP service. The following services are supported:

When sending email through a 3rd party SMTP service customers are responsible for setting up and paying for their license directly with the 3rd party SMTP provider. Lead Liaison will use the credentials for your 3rd party SMTP account to provision and setup support in our infrastructure. Using a 3rd party SMTP service allows email to be delivered on a campaign by campaign basis (one-off emails or complete workflows) through a 3rd party instead of Lead Liaison. One or more 3rd party services may be used. 

Follow the instructions below to setup your 3rd party SMTP service. 

Supported Operations

The following Lead Liaison services will still work when email is sent through the 3rd party SMTP service. The only distinct difference is that mail is ultimately delivered by the 3rd party, instead of Lead Liaison. Most of the above services have strict compliance rules about sending mail to people that only want to receive it and have provided their permission to do so. Customers that abuse the 3rd party services still risk getting banned from Lead Liaison. 

  • Bounces: When an email bounces the Bounced flag in Lead Liaison will be updated. 
  • Unsubscribes: When a contact unsubscribes they will be sent through Lead Liaison's standard unsubscribe process. 
  • Spam Complaints: Let's hope you don't have those (wink). If a contact hits the Spam button their email will be added to the Suppression List and the Do Not Email flag will be checked. 
  • Analytics: All email analytics (opens, sends, etc.) remain unchanged. 

Handling Bounces/Spam Complaints

Bounces and spam complaints are sent back to Lead Liaison's endpoint through an HTTP Post (Webhook). Lead Liaison's endpoint post-processes the notification, saves the information into the database and updates your instance appropriately.


Change Sending SMTP Service

To switch a campaign to send through a supported 3rd party SMTP service do the following:

For All Mail in a Workflow

  • Click the "Show Advanced Settings" link in Step 3 of your automation. 
  • Select your VMTA from the dropdown. 
  • If you do not see an option to "Select VMTA" then 3rd party services have not been configured. 

For Mass Mail

  • Under Advanced Settings (Optional) choose the desired VMTA next to "Select VMTA". 

3rd Party SMTP Setup Instructions

Domain Authentication

Make sure to setup authentication of your company's domain when sending mail through a 3rd party. When sending through Lead Liaison, authentication (DKIM, SPF Records, DomainKeys, etc.) is automatically handled for you. However, when sending through a 3rd party you're responsible for domain authentication. Domain authentication is not mandatory but strongly advised. Domain authentication should be setup on each sending domain used with the 3rd party.


  • Login to Sendgrid and navigate to Settings > Mail Settings > Event Notification
  • Add the Lead Liaison Endpoint above to the "HTTP Post URL" and select the 
    • "Bounced"
    • "Marked as Spam" and 
    • "Deferred" checkboxes.
  • Make sure to turn ON Event Notification. 
  • To view Sendgrid activities:


  • Login to Mailgun and add the Lead Liaison Endpoint to the " Webhooks For The Current Domain" section on each of the following tabs:
    • Bounces, 
    • Complaints and 
    • Logs



  • Outbound > Subaccounts and create a new Subaccount. Give it a unique name, something like "YourCompany-LL"

  • Settings > Sending Domains and add your mail domain. Make sure SPF and DKIM are configured and validated.

  • Settings > Sending Defaults, make sure the defaults are what you want. We suggest the defaults as shown below.

  • Settings > SMTP & API Info, create a unique API key for Lead Liaison email. 

  • Settings > Webhooks, create a new webhook using the Lead Liaison Endpoint in the "Post to URL".

Sending other Mail with your Mandrill Account?

If your Mandrill account is used to send other email and not just email via Lead Liaison then do not set any Triggers on your webhook. Create a rule instead. Follow these steps if you're using Mandrill for your email and Lead Liaison email:

  1. Create the webhook with a description and the Lead Liaison Endpoint. Do not select any triggers. Webhooks with triggers are applied to all emails for that account.
  2. Create 3 rules (Outbound > Rules) that causes email that is bounced, marked as spam, and soft-bounced to be sent to Lead Liaison's webhook. Below is an example of how the bounce Rule will look. 

Using a subaccount will help you filter and track Lead Liaison-specific traffic, while also using a unique API key for Lead Liaison will control the webhook and rules activity.

  • Proceed only if using Mandrill for Lead Liaison email only. 
  • Settings > Webhooks in the Trigger on Events section, check the following boxes:
    • Message Is Bounced
    • Message Is Marked As Spam
    • Message Is Soft-bounced

Adding Mandrill to Mailchimp

Mandrill is mainly a transactional email relay service. Before you can send from Mandrill, you'll need to make sure you connect your Mandrill account to Mailchimp and/or add Mandrill as an add-on service to your Mailchimp paid account. Follow these steps to add Mandrill from your Mailchimp account:

  • Go to the Transactional tab and click Get Started

  • Choose the number of blocks you need

  • Click Launch Mandrill


  • To setup event tracking go to My AccountEvent tracking (triggers).
  • Add the Endpoint URL above and check the box for "Bounce" and "Spam" from the list of events.

  • You will also have to verify the sender emails or domains. The sender here means the email or the domain of the email address used to send the email campaign from.

  • To verify the email/domain go under My Account > Sender & Domains > Sending Parameters and set the Domain List or the Sender List.

  • Make sure all the email addresses you are using to send emails from are verified or their domains are verified.

  • To turn off link reporting and opens go to My Account > Settings and set the following options under Email Tracking to Inactive:

Mailjet Notes

  • Lead Liaison inserts a special email header, X-Mailjet-Campaign, when mail is delivered through Mailjet to receive details on bounce and spam reports sent back to us. Mailjet uses this same email header as a way to consolidate Mailjet Campaigns within their interface. As a result, a new Mailjet Campaign (in the Mailjet dashboard) will be created for each email that's sent. This is usually not an issue as clients typically use Lead Liaison's email statistics dashboard to view consolidated campaign statistics. 
  • Mailjet tracks Unsubscribes as a link click while Lead Liaison does not. If you have link tracking enabled in Mailjet you'll likely see a higher number of link clicks in Mailjet's stats than you would in Lead Liaison's stats as Lead Liaison's link clicks do not include clicks on the Unsubscribe link.

To configure with Lead Liaison for bounce and spam reporting events do the following:

  1. Go to account senders:
  2. Add a new sender.
  3. Under the sender "Notification Preferences", check the "Bounces" and "Complaint" checkboxes and set the "HTTP" option to:


© 2021 Lead Liaison, LLC. All rights reserved.

13101 Preston Road Ste 110 – 159 Dallas, TX 75240 | T 888.895.3237 | F 630.566.8107 | Privacy Policy