We have a platform that offers the possibility to our clients to create and push custom audiences to facebook. We use the replace endpoint to replace existing user from the audiences.

The audiences synchronisation works up to a point, after which the operation_status stays blocked in this error: {"code":415,"description":"There was a problem replacing your customer list Custom Audience. Try again later."} and we can't replace the users anymore.

This is the endpoint used: https://graph.facebook.com/v13.0/<CUSTOM_AUDIENCE_ID>/usersreplace

Can't figure out what is causing this error.