There are a few ways to fix the “oops something went wrong” error; usually when you encounter this issue it isn’t due to a problem within the plugin, but with your settings. Here are a couple of ways you can check if something might be missing or incorrect.

Check the Mailchimp for WordPress log

Log in to your WordPress Admin and go to MC4WP > Other. Check to see if there is any error explaining why the form did not submit. For example the email address could be blocked by or be marked as fake email.

For example: 400 Bad Request. Invalid Resource. has signed up to a lot of lists very recently; we’re not allowing more signups for now.  means the email is banned by Mailchimp for being subscribed to too many lists in a short amount of time. Since this is a ban from Mailchimp, not from Mailchimp for WordPress, this is not something that we can solve from our side. We recommend testing with a new/fresh email.

Check the API log

Log in to your account, click on your account name on the right top and choose Account.
Click on Extra > API keys. Scroll down to see the latest calls to the API and their result.

Check your Mailchimp settings

Check if every field you’re using in your form is also present in your Mailchimp’s List fields and *|MERGE|* tags page, and that you’re using the correct settings. You can find this page in Mailchimp Dashboard > Lists > Your list > Settings.

Check the following:

  • Are you using the correct tags in your form? You should be using the tags mentioned under #5 (see below)
  • Do you have a field set to required in Mailchimp, but not in your form? (Check #3)
  • Are you using the correct field type in your form (see #2)? If, for example, you have a type="text" in use for your website input field, Mailchimp will return an error.

list fields and merge tags

The plugin checks for these things and will actively notify you if it finds anything wrong, but it’s a good idea to check everything if you run into trouble.

If you are integrating Mailchimp for WordPress with another plugin, the error messages will not show. We're working on making this easier, but keep in mind to check the above thoroughly for any mistakes!

Fix the error in custom forms

When you are using a custom form, or are integrating with Contact Form 7, there are a few other things to check for. Make sure you have checked everything listed above first (you will not receive error messages when you’re using another plugin!).

If the issue still persists, make sure you have prefixed every field that you would like to send to your Mailchimp list with mc4wp-.

Still not working?

Tried all the above and still not getting rid of the error? Contact the Premium helpdesk when you’re a Premium user, or open a new topic in the support forum.