I tested WowOptin with Brevo and ran into a deal-breaking issue. If a contact already exists in my Brevo account (for example, on another list), the form submission fails with a “server error.”

In Brevo, contacts are global, one email can belong to multiple lists. Other form plugins (like Kadence Advanced Forms) handle this correctly. If the contact already exists, they just get added to the new list. With WowOptin, it seems to only try to create the contact again, which Brevo blocks as a duplicate, instead of updating the existing contact and assigning them to the list.

This means I can’t add an existing subscriber to another list, which basically breaks most email marketing workflows. Has anyone else seen this problem with WowOptin + Brevo? Or found a fix?

Support told me they would get back to me on Sunday. Today is Thursday.