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Contacts and Leads from my system of record are not syncing to Mailchimp

Are you integrating CRM, Financials, or eCommerce software with Mailchimp, and yet some of the records from your CRM, Financials, or eCommerce database, Lists, Saved Searches, Campaigns, Marketing List, or List Views did not sync over to your Mailchimp Audience or Group?

Use case:

"I am wondering why it syncs only 353 contacts but my marketing list in CRM has 384 contacts!"

Here are the typical causes:

  • Archived records in Mailchimp
  • Previously unsubscribed or bounced
  • Invalid email address
  • Contact or Lead record does not have an email address (SyncApps uses the Standard email address field not the secondary email address fields)
  • Required fields are blank in CRM, Financials, or eCommerce software
  • Invalid Address mapping

Archived, Previously unsubscribed or bounced records

This is one of the common cases where a record is not synced because they were Archived, unsubscribed, or bounced in Mailchimp. For Archived records, you may need to unarchive them and unsubscribe in Mailchimp:

For resubscribing archived records, head to Step 2 of the Sync Profile setup and enabled the "Resubscribe Archived Records" then Save Changes, Reset Sync Process, and resync.


By default, when a Contact or Lead that was synced by SyncApps is then Archived in Mailchimp, on the next sync, that record will no longer be updated in Mailchimp. If you want them to be resubscribed and unarchive them in Mailchimp automatically so that they will be updated on the next sync, please enable this feature.

Note: This will only work for records that are synced(cached) by SyncApps. Meaning, if they are marked as archive prior to the sync and SyncApps hasn’t initially synced(cached) the records to Mailchimp, those will not be updated.

Invalid email address, Contact or Lead record does not have an email address, required fields are blank in CRM, Financials, or eCommerce Software

By default, SyncApps will ignore those records with no email address and also, Mailchimp will reject those email addresses that will not pass their standards. If the email address is valid yet it still won't sync, you may reach out to the Mailchimp support team so that they can validate those wanted email addresses and will now be synced to Mailchimp.

Getting, looks fake or invalid, please enter a real email address., code: 400?

For records with blank required fields, here's a good read.

Error 400: Your merge fields were invalid

Invalid Address Mapping to Mailchimp

 Mailchimp is strict when it comes to mapping the Address fields, even if a single address field is not populated with a value then Mailchimp will reject that Contact/Lead to be created. How can I ensure that these records will be synced? See the article below:

Integrate mailing address fields from CRM, eCommerce between Mailchimp

Records still not syncing? No worries! Reach out to our 24/7 Support team today for further investigation.


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