Verification email is disabled or missing
Sending the initial verification template returned not-sent. Product: enable it under Admin → Settings → Emails.
Why this happens
Same pattern as Resend verification email is disabled or missing / Password reset email is disabled or missing — template off or absent. Distinct from SMTP/Gmail transport failures (We could not send the verification email…).
Diagnose and fix
1. Admin → Settings → Emails — enable Auth verification template; save.
2. Confirm Require email verification matches your policy.
3. Ensure outbound mail works (SMTP settings / Gmail XOAUTH2).
4. Retry register or admin “Send verification.”