Can Wi-Fi work while LTE internet is down?
Yes. Wi-Fi is the local connection to the router. The router still needs a working SIM, signal, APN and plan to reach the internet.
Mobile dataMobile dataAPN settingsSouth Africa
Mobile data on but not working
Use this when your phone shows 4G, LTE or 5G but websites and apps will not load. The fix is usually to narrow down whether the problem is balance, signal, APN, phone settings or the network account.
Quick Answer
Meaning
Your phone has a mobile network connection, but the internet data session is not working correctly.
Most likely cause
Expired data, weak coverage, wrong APN, dual-SIM data selection, data saver settings, out-of-bundle block, or a provider-side account issue.
First thing to try
Turn flight mode on and off, check data balance and expiry, then test a simple webpage with Wi-Fi switched off.
Contact
Contact your mobile network through official support if the SIM has data but no device can browse, or if billing, Rica, SIM swap or account status is involved.
Reviewed by Riccardo Vallaro, Telecom & Mobile Services Specialist
Last reviewed: 20 May 2026
Sources we check: General consumer troubleshooting patterns, DataCost internal guide links, public provider self-service concepts, and South African prepaid user needs.
Why trust this: Guides are based on public operator pricing, USSD flows, official support pages, and South African prepaid user needs.
Found outdated info? Send a correction.
What It Usually Means
- The mobile-data toggle only means the phone is allowed to use mobile internet. It does not prove that your SIM has data, the APN is correct or the network session is active.
- Apps can also be blocked by data saver, background-data limits, private DNS, VPN settings or a weak signal indoors.
What to Try First
- Switch Wi-Fi off so you are testing mobile data only.
- Turn flight mode on for 20 seconds, then turn it off and wait for LTE or 5G to return.
- Check data balance, bundle type and expiry before buying another bundle.
- Restart the phone if the SIM was recently inserted, swapped or moved from another device.
Step-by-Step Fix
- Check whether calls or SMS work. If they do not, start with SIM or network registration rather than APN.
- Confirm the correct SIM is selected for mobile data on dual-SIM phones.
- Open one simple webpage in the browser, then test WhatsApp or app traffic after that.
- Disable VPN, private DNS, data saver or app-specific mobile-data blocks temporarily while testing.
- Check APN settings for your network if browsing still fails.
- If the same SIM fails in another phone, contact official network support with balance, location and time of failure.
When to Contact the Provider
- The SIM works in no device or the router reports SIM not detected.
- The router is network-locked or asks for an unlock code.
- The dashboard shows account, registration or activation errors.
- A reset does not restore the router or admin login details are unknown.
What Not to Do
DataCost is not the provider. Do not share OTPs, banking passwords, card details, PINs or personal identity documents with unofficial support channels.
- Do not factory-reset the router before noting the Wi-Fi name, admin login and APN profile.
- Do not share router admin passwords, OTPs or account details with unofficial support channels.
- Do not force SIM adapters or damaged SIM cards into the slot.
Related DataCost Guides
Related Fix Pages
FAQs
Should I reset my router first?
A power restart is safer as a first step. Factory reset only when you have the router login details and know how to restore APN and Wi-Fi settings.
Who should I contact if the router still fails?
Contact the mobile network for SIM, plan and APN issues, or the router seller/manufacturer for hardware and warranty issues.
Official Support Reminder
This is a general troubleshooting guide for South African consumers. Always confirm billing, payment, activation, meter, token, subscription and account-specific issues with the official provider.
Author and review notes
Written by Riccardo Vallaro
Telecom & Mobile Services Specialist
Mobile services and telecom professional with experience across VAS, carrier billing, mobile content, and African operator partnerships.
Reviewed / updated: 20 May 2026
Why trust this guide: Written as independent consumer help for South African mobile, electricity, decoder and router problems. Provider-specific account actions should be confirmed through official support.
Found something outdated? Send a correction.