When you add your WhatsApp number, the code window says when the code reached your phone, or why WhatsApp could not deliver it.
A message from one of your flows that WhatsApp did not deliver rings the bell with the reason, and Settings, Your WhatsApp shows the last one that failed.
Messages come most reliably after you write to xMap’s number: Settings, Your WhatsApp has Say hi on WhatsApp, which opens the chat, and for the next 24 hours every message comes straight through.