In order to be able to access our client accounts without needing to go through the two-factor authorization step (where it sends a code via SMS or email to them), we need to be added as a user on their account. To do that we log into our MailChimp account (Member Splash Demo) and click on Clients at the top right. From there choose Add Client and enter the email address associated with their MailChimp account (should be in the CRM). For the message to send them use the following:

This request is from Member Splash so that we can access your MailChimp account to generate an API key to connect it with our platform, assist with segments, etc. Please be sure to select the Administrator user role. If you have any questions please contact us at or by phone at 949-734-0758. Thanks!

Once they have added us you will see them listed on the clients screen and you can switch to their account.

Here is what I put in the ticket response when someone asks a MailChimp question for an account we don't have access to:

Happy to take a look at it. MailChimp uses two-factor authentication and anytime it sees someone logging in from a new device it requires a PIN. I'm sending a request right now for you to grant access to your account to our MailChimp account, that way I can log in without needing to get a PIN from you. When you get the request link if you can make sure to choose Administrator as the user role that will allow us to manage segments, etc. The request will go to the email address on your MailChimp account, which we show as XXX