OTP SMS not delivered in Nigeria? Check your route and sender ID before you look at the user’s phone. You control both. On Arkesel, a code sent on the promotional route is blocked on a line restricted by Do Not Disturb (DND), and it is worth confirming how any other provider treats it. Run the five checks below on one affected number, and adapt the user message further down.

Arkesel sends OTPs to Nigerian numbers, so where this guide gives route behaviour and lead times for our platform, it is describing our own process.

Why do OTP SMS not arrive in Nigeria?

There are four causes to rule out when a verification code goes missing on a Nigerian number:

• The wrong route. The code went out on a route that does not reach DND-restricted lines. Arkesel’s promotional route is one of these.
• A sender ID that is not registered for the job. Some providers require sender IDs to be registered in advance. One international aggregator’s Nigeria regulations page says that, on international traffic, some suppliers may require sender ID registration for MTN, and that without pre-registration the sender ID is replaced with a generic name. A code sent that way could arrive under a name your user does not recognise. On Arkesel, the sender ID has to be approved before you can send.
• Full DND on the recipient’s line. This matters when the message is not travelling on a route that reaches DND-restricted lines.
• A ported or recycled number. The number has moved to another network or now belongs to someone else.

Start with the route: a route that blocks DND-restricted lines fails for all those users at once, and a single recipient’s setting touches only that person. That is our judgement from the mechanism, not a measured share of tickets.

What is DND in Nigeria and how does it block SMS?

DND is a setting the subscriber controls, and the regulator created it. The consumer portal of the Nigerian Communications Commission (NCC) calls it a service “designed by the NCC (Nigerian Communications Commission) to protect Nigerian telecom consumers from unsolicited text messages”. Subscribers switch it on or off with the short code 2442, which works across all networks. Texting STOP to 2442 activates full DND, which “does not allow the consumer to receive any unsolicited messages”.

The duty to run the block falls on network operators. The NCC directed all Mobile Network Operators to “implement the Do-Not-Disturb (DND) service and dedicate the short code” 2442. An NCC consumer article cites the Consumer Code of Practice Regulation 2007 as the platform for that direction. Those regulations were revoked by the Nigerian Communications (Consumer Code of Practice) Regulations, 2024, which preserve things done under them without saying what that means for this direction. A separate NCC article says providers had to “integrate the DND function into their system effective from 1st July 2016”.

That same article defines two settings. Under full DND, a subscriber “decides not to receive any SMS service from any telecom service provider”. Under partial DND, a subscriber decides not to get “a specific type of promotional or commercial communication”. None of the three NCC consumer articles quoted here mentions OTPs.

Does the NCC exempt transactional or OTP SMS from DND?

The direct answer is that a 2018 NCC framework comes close without establishing an OTP exemption from DND, and the 2024 Consumer Code regulations name neither OTPs nor DND. The NCC’s Value Added Services and Aggregator Framework, amended March 2018, says “SMS information messages can be sent to all categories of subscribers as long as they are not marketing information”. Chapter 3 of the framework lists do-not-disturb, opt-in and neutral subscribers, so we read “all categories” as including DND numbers. That is our reading, not the NCC’s statement. The framework names neither OTPs nor DND routing, and we could not confirm that it is still in force.

The NCC’s other wording does not settle the question either. Clause 3.1 of the same framework tells operators to keep a central DND database and, with aggregators, to ensure that “no adverts are sent to any telephone number on the database”. Clause 5.1 defines advertising as “non-confidential promotional messages directed towards providing marketing information on products, goods and services”. Neither these clauses nor the consumer articles quoted above say how an OTP should be treated on a full DND line, and a later NCC edition or circular could change this picture.

The NCC pages above do not define a promotional or transactional route. We treat that split as operator and aggregator practice, and the table separates the two layers:

So citing the NCC will not settle a delivery problem. Ask your provider which route carries your OTPs, and get the answer in writing.

What is the transactional (DND) route and how do you get a sender ID whitelisted on it?

For transactional SMS in Nigeria, including OTPs, the DND route is the path Arkesel uses, and it lets verification traffic reach DND-restricted lines. To use it, you whitelist a sender ID, which means submitting that sender ID and your company documents for approval for this route.

The two routes clear at different speeds. A promotional sender ID is approved in about 24–48 hours, so a team under launch pressure can be tempted to send codes on it. Those codes are then blocked on DND-restricted lines, and on Arkesel you are still charged for each send. Our guide to the difference between transactional and promotional bulk SMS explains which messages belong where.

Before you plan around whitelisting, check that you qualify for Nigeria sender ID registration for OTPs. Only a company registered in Nigeria can register a Nigerian sender ID, and the ID must be 11 characters or fewer and not all-numeric. Arkesel’s DND route does not support international messages, and a business not registered in Nigeria has its messages classified as international, so the guidance on this route applies to companies based in Nigeria. If your company is registered elsewhere, contact Arkesel before you plan a launch in Nigeria. For the DND route, Arkesel asks a Nigerian-registered company for:

• CAC certificate
• Operational licence, such as a CBN licence if you are a financial institution
• Office address
• Your preferred sender ID
• Up to three message samples, which should be your real OTP wording
• Company name
• Website URL

As of 17 September 2026, whitelisting takes about 4–6 weeks, so start well before the launch it supports. If your sender ID is already approved or whitelisted with another provider, it still goes through the full registration at Arkesel, including this whitelisting. That can run in parallel while you keep sending through your current provider.

Once the sender ID is whitelisted, routing is automatic. Every OTP and transactional send from that ID uses the DND route, and you do not request it per send. Keep promotional campaigns on a separately registered sender ID.

If your company is registered in Nigeria and has a launch coming up, talk to Arkesel about getting your Nigerian sender ID whitelisted.

OTP SMS not delivered in Nigeria: five checks to run

Run these in order, using one affected number.

1. Confirm the route and sender ID status. Ask your provider which route your OTP sender ID is on and whether whitelisting is complete. If your provider confirms the promotional route, or the ID has approval but no whitelisting yet, expect blocked codes on DND-restricted lines. That is how Arkesel’s promotional route behaves, so ask any other provider to confirm its own.
2. Read the delivery report for that recipient. Arkesel shows per-recipient status, normally within about a minute of delivery. The platform does not send failure alerts, so your team or your system has to read the report. Our guide to reading SMS delivery reports covers the statuses.
   • If the report shows a failure, look at the route, or go to check 3. Ask your provider how a DND block appears in its report rather than guessing.
   • If the status is delivered and the user sees no code, ask them to look for it under an unfamiliar sender name. One aggregator documents sender ID replacement on international traffic, as in the second cause above. If the code is there, send your provider the number, the send time and the name shown, and ask whether your traffic goes out as local or international and whether your sender ID is registered for that route. If not, go to checks 4 and 5.
   • If the status shows no delivery confirmation yet, wait and look the message up again before you resend, then use the branch that applies.
3. Ask the user to text STATUS to 2442. If DND is on and you are not on the DND route, that is the likely cause. If DND is on and your sender ID is whitelisted, DND should not be blocking the code, so send your provider the number and the send time. If DND is off, carry on.
4. Check whether the number has changed networks or hands. Ask the user whether they recently moved network and whether the number on the account is still theirs. A delivered status with nothing on the user’s phone, or a stranger reporting your code, can mean this. If the number has moved network, send your provider the number and the send time, say that it moved, and ask how its route handles ported numbers. If the number is no longer theirs, update it through another contact detail before you send another code.
5. Compare the send, delivery and expiry times. With Arkesel you set the expiry between 1–10 minutes. A code delivered after its expiry fails at verification, and the user may report that as a code that never worked. Our guide to OTP expiry and rate limiting covers how to set that window.

If the report still shows a failure, send your provider the number and the send time and ask for the reason. Otherwise, look at the integration itself. Our list of common OTP API integration issues covers the failures that have nothing to do with DND.

How can a user check or remove DND on their Nigerian number?

A user can text STATUS to 2442 to check their setting, ALLOW to 2442 to leave DND entirely, or HELP to 2442 to set up partial DND. All of these commands come from the NCC’s DND page. You can adapt this message for your support team:

We sent your verification code, but it has not reached your phone. A Do Not Disturb (DND) setting on your line may be the reason. To check, text STATUS to 2442. If DND is on and you are happy to change it, text ALLOW to 2442 to leave DND entirely, then request a new code. This is your choice, and you can turn full DND back on at any time by texting STOP to 2442.

The NCC presents DND as the consumer’s own decision, so offer this as an option and never make it a condition of service. Leaving DND also lets back in the promotional messages the person chose to block.

Be careful with partial DND, which is why the message above leaves it out. The NCC’s categories include texting 1 to 2442 for banking, insurance and financial products, but it describes these as types of promotional or commercial message and does not say OTPs fall under any of them. Do not promise a user that a category will release their code.

If your company is registered in Nigeria, treat the message as a stopgap while your whitelisting is in progress. Once your sender ID is on the DND route, you should not need to ask users to change their DND setting.

Why would an OTP reach the wrong person in Nigeria?

An OTP can reach a stranger when the number has been recycled, meaning the network reassigned it to a new subscriber after the previous one stopped using it. The send has worked in that case, but the number on your records no longer belongs to your user.

The regulator has acknowledged the wider problem. In February 2026 the NCC published a consultation paper on a Telecoms Identity Risk Management System (TIRMS), a platform to help prevent fraud stemming from churned, swapped and barred numbers. Its first phase focuses on churned, recycled and swapped numbers. This is a proposal that was open for comment until 20 March 2026, not a rule we can tell you is in force.

Porting is a separate case. The international aggregator’s page cited earlier records that Nigeria supports mobile number portability, which lets a subscriber keep a number when they change network. That can change how a message is routed, which is why check 4 asks your provider about it. Number lookup services are a general way to find out whether a number has moved, but Arkesel does not offer a lookup for Nigerian numbers.

We recommend not retrying blindly when a delivered status could mean a change of holder. For accounts that have been dormant for a long time, confirm the number through another contact detail before you send a code that unlocks anything sensitive.

Setting up OTP SMS for Nigeria on Arkesel

Arkesel’s SMS Platform and Phone Number Verification are available to senders in Nigeria. For a company registered in Nigeria, a setup that avoids the failures above looks like this:

1. Start sender ID whitelisting first, using the documents listed earlier, because it takes the longest.
2. Integrate api/otp/generate and api/otp/verify. Our OTP endpoint documentation has the details, and our walkthrough shows how to integrate an SMS OTP API step by step. The medium field is required on each request and has no default, so set it to sms. Nigerian numbers receive Arkesel OTPs by SMS only, because voice OTP and USSD retrieval are for Ghanaian numbers.
3. Choose your code settings. Codes can run to 6–15 digits, and you set the expiry within 1–10 minutes.
4. Build your own resend logic. The API has no automatic channel fallback, so a resend is a new SMS request that you send. OTPs are billed per OTP sent, not per successful verification, so limit resends. See current pricing.
5. Read your delivery reports. There are no failure alerts, so make checking them part of your monitoring.

Arkesel’s direct mobile network connections are in Ghana, and Nigerian traffic reaches the recipient’s network through aggregation and onward routing. DND is applied on the Nigerian network side, so the fix is a whitelisted sender ID and not a setting in your code. For the wider set of SMS endpoints, see Arkesel’s Nigeria developer API page.

Fix the route before your next release

If codes are failing today, run checks 1 to 3 on one affected number and send the DND message to users who are blocked. If the route is the cause and your company is registered in Nigeria, start whitelisting now so that it is in place before your next launch.

Related Articles

• Phone Number Verification in Nigeria: Cut Fake Signups
• OTP Not Delivered in Ghana? Find Out Why on MTN or Telecel
• Best OTP API Provider 2026: Twilio vs Vonage vs Arkesel Compared
• SMS Pumping Fraud Prevention: How to Detect and Stop Artificially Inflated Traffic
• OTP for Fintech Banking: Secure Transactions at Scale
• SMS OTP vs Authenticator App vs Email OTP (2026 Guide)
• OTP Security Best Practices: A Developer’s Guide to Secure Transactions (2026)
• What Is an OTP Code? How One-Time Passwords Work

If your company is registered in Nigeria, contact Arkesel to whitelist a transactional sender ID, then see phone number verification for Nigeria to send OTPs from one API, or create your Arkesel account.

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