The page fires at 02:13. A student cannot sign in, support is asleep, and the dashboard shows a healthy login endpoint. The missing signal was earlier: a verification code was requested repeatedly, then never accepted. That is a delivery and recovery problem, not merely a choice between two input fields.
Short answer: email and phone verification protect different security boundaries, so choose based on identity stability, abuse exposure, and the recovery path you can operate when delivery fails.
I've been paged for missed jobs and duplicate deliveries in production. The same operational smell appears here: a system can return 200 while the user experience is already broken. Treat a code request like a job with a deadline, a retry budget, and an audit trail.
What should an education app verify first?
Start by naming the asset. For a classroom product, the account may hold grades, guardian contacts, or a teacher's roster. An email address is often stable across a school year, but school mailboxes can be disabled during a transfer. A phone number can reach a person quickly, yet numbers are recycled and shared devices are common. Neither channel proves that the person is the rightful owner forever.
