A verification code fails to arrive because of the wrong order of actions far more often than because of a faulty SIM card: someone brings the slot online and immediately clicks "send code," while the card has not yet registered on the network. Here is the correct three-step order, why doing it backwards loses the code, how long the free window lasts, and what to do when the service's procedure runs longer than that.
The right order: three steps before requesting a code
Step one — bring the slot online from your account. A slot under offline rental does not stay connected all the time; it comes online on request, and that is a separate action, not something automatic in the background. Step two — wait for the card to register on the network. That takes a moment: a SIM card needs a few seconds to find the network, register, and get a channel ready for SMS, and the status in your account should switch to "online" before you move on. Step three — only now request the code on the service's side: click "send SMS," "get code," "sign in by phone number." Swap steps one and three and the odds of losing the code climb sharply.
Why the reverse order loses the code
The service on the other end does not wait: the moment you click "send code," it fires the SMS right away. If the slot is not online yet, or the card has not finished registering, the message arrives at a number not physically ready to receive it — and it is simply not delivered. Most services do not let you resend a code immediately: a minute, sometimes more, plus a cap on attempts per hour. One ordering mistake costs several minutes where the correct sequence delivers the code in seconds.
The free window: how long it lasts and how to fit inside it
A free window lasts 1 hour and is available up to 2 times a day per slot — plenty of time to register the card and receive one code, provided you follow the three-step order. To fit inside it, bring the slot online right before you move to the code-request form, not ahead of time "just in case": the hour counts from the moment you switch the slot on, not from the moment you actually need the code. If the code does not arrive on the first try, one more free window remains for that slot the same day — just try again without buying anything extra.
When the window is not enough — buy guaranteed airtime
An hour is not enough when the service's procedure drags on: multi-step verification with a moderation wait, a call instead of an SMS at an unpredictable time, repeated sign-in attempts spaced apart. In that case, do not chase the free window — buy guaranteed airtime instead, a paid package for 1, 3, 6, 12 or 24 hours. For the whole paid period the slot stays online without interruption and takes priority over other owners' free windows, so the code reaches the card online even if the procedure takes several hours.
Signs the slot is already online, and common beginner mistakes
The slot is online once the status switches to "online" and a countdown timer starts for the window or package — before that, the card is still registering, and it is too early to request a code. Three mistakes come up most often. First, requesting the code the very second the slot is switched on, before the card has registered. Second, switching the slot on hours ahead of the actual attempt, so the window runs out before the code is ever needed. Third, retrying without a pause: if the code does not arrive, there is no need to switch the slot off and back on — just confirm the status still reads "online" and request the code again within the same window.
Frequently Asked Questions
How long should I wait after switching the slot on before requesting a code?
Usually just a few seconds — wait until the status in your account switches to "online," and only then move to the code-request form on the service.
What happens if the code still does not arrive within the free window?
Nothing to worry about: up to 2 free windows are available for the same slot each day, so you can try again in the next window or buy guaranteed airtime right away if timing is critical.
Do I need to switch the slot on again for every new attempt within the hour?
No — as long as the timer for the free window or the paid package has not run out, the slot stays online continuously, and repeated code requests within that time do not require switching it on again.
Check a slot's status and bring it online before requesting a code in the offline SMS rental section. How free windows differ from guaranteed airtime, and how slot ownership works overall, is covered in what offline number rental is. How offline ownership compares with regular rental in terms of reception availability is covered in offline rental versus regular rental, and the general mechanics of receiving a confirmation code are covered in what an OTP code is.