error when fillling in a form

Hi there,

We connected MC4WP and it says so in settings, also refreshed the list through MC4WP > mailchimp > renew lists AND choose a list in MC4WP > form > settings but still the error below when filling in an events manager form.
When we fill in a CF7 form we do not get this error but also no new subscription to the list in mailchimp it seems (unless there is a big delay).
We could use some help, than you in advance!

[2020-09-25 14:18:05] ERROR: Events Manager > Mailchimp API Error: Not Found. Resource Not Found. The requested resource could not be found.
Request: POST https://us17.api.mailchimp.com/3.0/lists/927b967b8a/members – {“status”:”pending”,”email_address”:”elax**@ho*****.com”,”interests”:{},”merge_fields”:{},”email_type”:”html”,”ip_signup”:”85.146.8.108″,”tags”:[]}
Response: 404 Not Found – {“type”:”http://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/”,”title”:”Resource Not Found”,”status”:404,”detail”:”The requested resource could not be found.”,”instance”:”92c70ae2-4448-488f-b083-f723e6dc9060″}

The page I need help with: [log in to see the link]