When you send contacts to a list to MailChimp, you will get an email from Method giving you a summary of the export:
This email will inform you when a contact is not sent.
Method has filtered the contact
Method will not a send a contact to MailChimp if:
- The contact has unsubscribed from receiving marketing emails (see creating customers or leads).
- The contact has a missing or invalid email address.
Currently, at this time, there is no way to override this filter.
MailChimp has rejected the contact
There are a few reasons why MailChimp will not accept a contact, and this mirrors the same import errors you would get if you were importing contacts directly in MailChimp.