MailChimp Integration error: MMERGE1 Needs to be provided?


Hi all,

On our latest Q4 landing pages we’re asking to provide just an email address which is being fed into MailChimp. However, like before in Q3, when we get a conversion we also get an integration error:

“MailChimp experienced an error processing your lead: MMERGE1 must be provided - Please enter a value”

No idea where this is coming from. Does any of you know how to solve this problem or what I’m doing wrong?



Hi Niklas - it looks like there’s a field in MailChimp that’s marked as required that you’re not sending data too.

Usually the first custom field you create in MailChimp gets “MERGE1” as it’s merge tag, but it could also be that you just have a field named MMERGE1 that’s marked as required.

Either way, you should be able to get rid of the integration error by either mapping a field from Unbounce to that field or going into your MailChimp account and removing the “required” checkbox.

In MailChimp, head to lists, choose the list you’re sending your Unbounce leads to, the click on the Settings drop down and choose "List fields and *|MERGE|* tags. You should see that field listed there and you’ll be able to remove the required check.


Thanks, Quinn - we will test this and see if it works.