Troubleshooting ESP Sync

ESP Sync makes it easier to build and test your emails in Litmus. There are several reasons why your email may not be syncing to your ESP or failing to send in a draft from your ESP. The following sections have helpful troubleshooting tips.


NOTE: A best practice is if you ever encounter sync errors, please try re-syncing or make the appropriate changes and re-save your document to attempt a re-sync.


  • Campaign name is duplicated: You cannot sync an email with a title that already exists in your ESP. To fix this, simply change the title of your Builder document.
  • Email is no longer in a draft state: If an email was previously synced and moved outside of a draft state in the ESP such as being sent or deleted, the sync will be unsuccessful. You will have to duplicate the document to attempt a new sync.

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  • Acoustic Campaign does not support image syncing. You cannot sync images from Builder to Acoustic due to Acoustic's lack of API support.

Campaign Monitor

  • Campaign Monitor templates require template tags. You need at least one <singleline>, <multiline>, or <img editable>, <repeatertitle>, <tableofcontents>, and <unsubscribe> tag in your template when syncing to Campaign Monitor. Simply update your email/template with these changes and re-save to re-sync.
  • Campaign Monitor emails and templates require view online and unsubscribe links for every sync. Simply update your email/template with these changes and re-save to re-sync.

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  • You must choose an email group for the selected email in Eloqua. To trigger a test from Eloqua, the email must belong to an Eloqua Email group.

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  • You have an unverified domain in Mailchimp. If you are syncing to Mailchimp, we populate a campaign from email address with the email address of the Mailchimp account. Mailchimp requires the from email address domain to be verified in order to sync properly. You can learn more about how to verify domains in Mailchimp.
  • Mailchimp's gallery has an upload limit of 1GB. If you exceed your storage limit in Mailchimp's gallery by attempting to sync images uploaded from Builder, the sync will error. Delete images to fall under the 1GB limit and re-try syncing.
  • Mailchimp Template names have a character limit of 50 characters. If your email name in Litmus is greater than 50 characters, your sync will fail. This limitation does not extend to Mailchimp Campaigns.
  • Template code changed after being synced. Mailchimp uses an HTML Linter tool to run the code inline which may move some information located in the <head> to the <body>. They run this process for templates, but not for campaigns. If you are noticing these changes being made and want further information, please contact Mailchimp Support.

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  • Syncing to Marketo from Builder will fail if you try to sync an email that contains an emoji that is not using the emoji's HTML entity. You may see a message stating the Marketo API request failed with 'System error'.
  • Marketo workspaces and partitions are not supported. We currently do not support the use of ESP Sync with Workspaces and Partitions in Marketo.
  • Syncing to Campaigns requires additional setup. If you sync to Marketo Campaigns, not just Templates, you must approve the Litmus Base Email Template in Design Studio. This can be found in Design Studio at the following path: Design Studio/Default/Email Templates/LitmusApi. There will be an email template in the LitmusApi folder—please ensure that is approved.

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Salesforce Marketing Cloud

  • Salesforce Marketing Cloud (SFMC) accounts that utilize the Approval functionality in Content Builder. Sync functionality will not work unless the email is in an Approved state for sending with Content builder approvals.
  • Your SFMC account must have the All Subscribers List setting enabled. This setting is disabled by default and can be enabled by submitting a request through SFMC support to allow ESP Sync to function properly.
  • The selected email did not pass validation with your email service provider (ESP). This is commonly due to the email containing AMPscript when selecting a draft for review in Spam Testing, Proof or Previews & QA. Due to limitations of the SFMC API, the AMPscript attributes cannot be resolved when sending in via ESP Sync. For any draft email displaying this error, you can send the email to Litmus manually. When performing a subscriber preview and test send, these attributes can be resolved via the chosen subscriber or data extension.
  • Request contained some validation errors. This error occurs when you try to sync your Builder document and the name of your email contains the = and/or > characters. The = and > characters are prohibited by SFMC. Remove any prohibited characters and attempt a re-sync.
  • Syncing uploaded images. If your team is using uploaded images in Builder, you must have unique names for those images. ESP Sync will fail if an asset already exists in your Marketing Cloud instance with the same name as the image you are trying to sync. The Predictable File URLs Content Builder setting is not currently supported. You will need to disable it in order to sync local images from Builder successfully. Images will only sync to the top-level folder, even if you've selected a sub-folder for your email to be synced to.


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