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The short answer
Zenith Bank's *966# usually fails for one of five reasons: you are dialling from a number not linked to the account, the line has never been set up for *966#, your PIN is locked, the network is congested, or the profile or account has been blocked (for example with *966*911#). Check them in that order; the first three you can fix yourself, while a blocked profile or a restricted account needs Zenith to lift it.
When *966# stops working, the message on screen is often vague: "connection problem", "invalid MMI code", "service unavailable" or simply nothing. The cause is rarely the code itself. Work through the checks below before you queue at a branch.
1. Wrong phone number
*966# recognises you by the phone number on your account. If you changed SIMs, ported networks, or the account was opened with an old number, the service will not find your profile. Signs: the menu offers to open a new account, or says you are not registered.
- Check which number receives your Zenith debit alerts. That is normally the linked line.
- If it is an old number you no longer have, the number must be changed by Zenith; see changing your Zenith phone number.
- On a dual-SIM phone, make sure the call goes out on the right SIM.
2. Never set up on this line
Having an account is not the same as being registered for *966#. The first time you dial, the service asks you to create a 4-digit PIN, and some versions ask for your card or account details. If you skipped that or it timed out, start again with *966#. Our guide to setting up and resetting the *966# PIN covers it.
3. PIN locked or forgotten
Several wrong PIN entries can lock the service. Investdata's summary lists *966*60# for resetting the PIN. If reset is refused, the bank may need to reactivate the profile. Do not keep guessing; each wrong attempt can extend the lock.
4. Network and phone problems
| Symptom | Likely cause | What to do |
|---|---|---|
| "Connection problem or invalid MMI code" | Network congestion or USSD gateway issue | Wait 10 to 30 minutes and retry; try at a quieter time |
| Session ends before you finish | USSD timeout | Use a one-step string such as *966*00# instead of the menu |
| Nothing happens | No signal, line barred, or roaming | Check signal; USSD may not work while roaming, so ask your network |
| Works on one network, not another | Network-side outage | Wait, or use the app |
A USSD transaction that times out mid-way is the riskiest case. Before you repeat a transfer, check your balance or alert to see whether the first attempt went through. Repeating blindly is how people pay twice.
5. Profile blocked or account restricted
If you, or someone with access to your phone, dialled *966*911#, the account is blocked as a security measure; Investdata's 2019 report describes it as the code for customers who think their account is compromised or have lost their card. Unblocking is done by Zenith, not by dialling again; expect to confirm your identity at a branch or through the contact centre.
Separately, the whole account may be under Post No Debit, for instance if BVN or NIN details are missing. The CBN's December 2023 directive, reported by Nairametrics, set PND for accounts without BVN or NIN. In that case *966# will show your balance but refuse debits. See Zenith account restricted or PND.
Lost phone or stolen SIM
If *966# stopped working because your phone or SIM is gone, the priority changes from fixing the service to protecting the account. Ask your network to block the SIM, then block the Zenith account. Investdata's report says *966*911# is dialled from the registered number, so if you no longer have that SIM, call the contact centre on the number on your card instead. When you get a replacement SIM with the same number, you will need to set up *966# again, and Zenith may ask you to visit a branch before it lifts the block.
What to check first
- Is the SIM in use the one on your account?
- Have you created a *966# PIN on this line?
- Is the PIN locked? Try *966*60#.
- Is there signal and are you in Nigeria, not roaming?
- Did anyone use *966*911#, or has Zenith told you the account is restricted?
- If all else is fine, try the Zenith app or internet banking to see whether the problem is USSD only.
Getting help from Zenith
We could not confirm Zenith's contact numbers on its website in October 2026, so use the number printed on the back of your debit card or the contacts shown in the Zenith app, and avoid numbers posted in social media comments. Give the date and time of the failure, the network, and any message on screen; never your PIN. If a debit was taken without the service being delivered, the CBN's complaints process asks you to complain to the bank first and allow time for it to resolve, then escalate to the CBN Consumer Protection Department with your evidence.
Where Pryme fits
USSD depends on the network and the SIM, which is also its weak point for fraud; see USSD banking fraud. Pryme does not use USSD or SMS codes; the app relies on an authenticator and a transaction PIN (security).
Questions people ask
Why is Zenith *966# not working on my phone?
Usually because the line is not the one linked to your account, the *966# PIN has not been set up or is locked, or the network is congested. A blocked or restricted account also stops debits.
How do I reactivate Zenith *966#?
If you blocked it with *966*911#, Zenith must unblock it after confirming your identity. If the PIN is locked, try *966*60#.
Why does *966# say invalid MMI code?
Normally a network or gateway issue. Wait and retry, or use the Zenith app.
Can I use Zenith *966# with a new SIM?
Only if the new SIM has the same number. A new number must first be updated on your account by Zenith.
Sources
- Investdata: Zenith Bank unveils account blocking code *966*911# (7 Jan 2019) · accessed Oct 2026
- TechCabal: USSD codes for Zenith, Polaris, First and Union Banks (2023) · accessed Oct 2026
- Nairametrics: CBN to PND any bank account or wallet without BVN, NIN (1 Dec 2023) · accessed Oct 2026
- CBN: Complaints Management, Consumer Protection Department · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.