Why didn't my user receive their one-time passcode?
The most common cause is deliberate: Forte silently skips sending when no user owns that contact, or when the contact is unverified on an account that already has a verified owner — the response looks identical either way to prevent account-existence probing.
Beyond that, resends are throttled to one per 60 seconds and codes expire after 10 minutes, so have the user wait out the cooldown and request a new code.