Many clients use Mailchimp service to gather email addresses from their own clients to then send the occassional newsletter. Nothing is more frustrating than finding their emails are being either sent to spam folders or are being marked as potential spam by email services, particularly Google’s GSuite and Gmail.
This is very similar to the issue in our other blog post titled Spam Proofing Clients’ Email but this solution is specific to Mailchimp.
Even though you may have authenticated your email with Mailchimp, you must also set up custom DKIM authentication for your domain and include Mailchimp in your SPF record. Inbox Service Providers (ISPs), like Google, Yahoo, and Microsoft, use DKIM and SPF authentication as a way to scan incoming emails for spam or spoofed addresses. Emails that fail authentication are more likely to arrive in a spam or junk folder.

The fix is fairly easy once you know how to resolve it. This article from Mailchimp will give you step-by-step direction (and video) on how to add both CNAME and Text records to your DNS.
Note: We recently had to work with a domain purchased from Wix. Their CNAME records will append the url to the end of the host record. This seems to be a Wix idiosynchracy. We do not recommend purchasing domains from Wix. Purchase directly from Google Domains.
For your clients’ sake, be sure to properly authenticate with DKIM. Plan on 1 – 2 hours of time depending on where their domain is hosted.