Carriers often block Chinese SMS as spam. A Chinese SIM is the reliable fix.
Your carrier likely blocks Chinese SMS as spam.
What you'll see
If your phone works fine but the code never comes, the problem is the route, not your phone:
"Code not received" · "Resend failed"
中国 App 里显示为：未收到验证码 / 重发失败
Error-text level: L2 (observed wording). Exact in-app strings are being verified against a live device.
Why it happens
Two things block it: your carrier may treat Chinese numbers as spam, and the Chinese app's SMS provider may have no direct route to your carrier.
Fastest fix, free:Call your carrier and ask them to unblock SMS from Chinese numbers, then tap resend — or use a Chinese SIM card, which solves it outright.
Last verified:2026-09-20 ·
Confidence:Multiple sources (pending first-hand verification)
The full fix sequence (free)
Wait 60 seconds and tap "Send" again.
Restart your phone.
Try a different phone number.
Call your carrier and ask them to unblock SMS from Chinese numbers.
Use a Chinese SIM card.
When the fast fix isn't enough
In the kit
A Chinese SIM is the real fix — and you need one for 12306 anyway.
1. Where to buy a SIM at the airport
Booth locations and what ID to bring, so you are not stranded at arrivals.
2. The trigger matrix
Which carriers block Chinese SMS most, so you know before you fly.