Invalid Resource. Your merge fields were invalid. Date of Birth

Hello,

I use Buddypress and Mailchimp on my website.

When a user registers via the Buddypress registration form, he is not registered on Mailchimp by MC4! WP. The logs give me the following indication:

ERROR: User Sync > Error subscribing or updating user 23836: Bad Request. Invalid Resource. Your merge fields were invalid.
– DDN : Please enter the date
Request: PATCH https://us6.api.mailchimp.com/3.0/lists/79f6f2346f/members/df630faca0bef5e5822378f3563d7d64 – {“email_address”:”cora*******@gm***.com”,”interests”:{“0e54baaf78″:false,”ca75fc9062″:false,”29a9dd5b4a”:true,”6b7a9b4c27″:false,”d2c367d1bd”:false,”a748062830″:false,”433452c116″:false,”e7606dfcee”:false,”e571723cee”:false,”83b3375e11″:false},”merge_fields”:{“FNAME”:”Coraline”,”LNAME”:”Palis”,”NAME”:”Coraline Palis”,”USERID”:23836,”DDN”:”23\/08\/1985″,”SEXE”:”Femme”,”QUALITE”:false,”PAYS”:”France”,”PMPLEVELID”:1,”PMPLEVEL”:”Membre gratuit”},”status”:”subscribed”,”email_type”:”html”,”tags”:[]}
Response: 400 Bad Request – {“type”:”https://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/”,”title”:”Invalid Resource”,”status”:400,”detail”:”Your merge fields were invalid.”,”instance”:”018e01f1-76ee-4961-9e0a-efbcbdace7a4″,”errors”:[{“field”:”DDN”,”message”:”Please enter the date”}]}

The problem seems to come from the format of the date of birth which is transmitted in this form by the plugin: 23\/08\/1985 which prevents registration with Mailchimp in a standard date field.

Do you have any idea how to fix this please?

Thank you in advance for your reply.