We are experiencing an issue where WhatsApp flows using version 4.0 are not being delivered to selected devices, specifically iOS devices.
Details: message id - wamid.HBgMOTE5OTY3NTUxMDUyFQIAERgSMUNBNkNBQTdGNUIxRTdBMDA5AA==
Error JSON message - [{"code":131026,"title":"Message undeliverable","message":"Message undeliverable","error_data":{"details":"Message Undeliverable."},"href":"https://developers.facebook.com/docs/whatsapp/cloud-api/support/error-codes/"}]}]},"field":"messages"}]
WhatsApp Version: 2.24.8.78
Please note that version 4.0 is an "Early Release" version (see the version table), which has some implications on message delivery.
The attached docs should explain in more detail. Hope this helps.