Mobile Data Not Working? How to Fix It on Android and iPhone

By Ammar Aslam · Updated September 29, 2026 · 3 min read

Your phone shows signal bars, but apps won't load. Or mobile data stopped working after travelling or changing SIMs. Here's how to troubleshoot mobile data step by step.

1. Check the basics

Make sure Mobile data is turned on in Quick Settings.
Check you have an active data package and balance.
For dual-SIM phones, check the correct SIM is selected for data.
Turn off Wi-Fi to make sure the phone isn't stuck on a bad Wi-Fi network.

2. Toggle Airplane mode

Turn Airplane mode on for 10 seconds, then off. This forces a fresh network connection.

3. Restart the phone

4. Check Data Saver and app restrictions

Data Saver or per-app restrictions may block certain apps. See mobile data settings.

5. Check network mode

In SIM or Mobile network settings, set Preferred network type to automatic (5G/4G/3G/2G). Try switching between 4G and 5G if one is unstable.

6. Reset APN settings

The APN tells your phone how to connect to your network's data service. Wrong APN settings are common after changing SIMs.

Android: Settings → Mobile network → Access Point Names → menu → Reset to default.
iPhone: Settings → Mobile Data → Mobile Data Network → Reset Settings (if shown).

Your network's website lists correct APN settings if needed.

7. Roaming

If you're abroad, Data roaming must be on and your SIM must have a roaming package. Roaming charges can be high; check first.

8. Turn off VPN and Private DNS

A VPN or custom Private DNS can block data. Turn them off to test.

9. Reset network settings

Android: Reset Wi-Fi, mobile & Bluetooth. iPhone: Reset Network Settings. This resets APN and network preferences.

10. Check the SIM

Reinsert the SIM, test it in another phone, or get a replacement. See SIM card not detected.

Signal and area problems

Thick walls, basements and remote areas weaken signal. Check your network's coverage map or outage updates, and try moving near a window.

Quick order: Airplane mode → restart → APN reset → network settings reset → contact your network.

Mobile data issues on a new or imported phone

If a newly bought or imported phone gets signal but no data:

Check that the phone supports your network's 4G/5G bands; some imported models don't support all local frequencies.
In some countries, imported phones must be registered with the telecom regulator, otherwise the network blocks them after a period.
Make sure the phone isn't locked to a foreign carrier.
Reset APN settings as described above.

Mobile data works but is very slow

Check if you've used up your high-speed allowance; some packages slow down after a limit.
Try switching between 4G and 5G modes.
Move closer to a window or outdoors to see if signal improves.
Turn off Data Saver or battery saver modes that limit background data.
Test at different times; network congestion peaks in the evening.

When to contact your network

If you've tried the steps above, contact your network through its official app, helpline or service centre. Tell them your phone model, location, what you've tried, and whether the SIM works in another phone. They can check for area outages, SIM provisioning problems or blocked services. Keep your ID ready if you need a SIM replacement.

Frequently asked questions

Why do I have 4G but no internet?

Usually APN problems, exhausted data balance or network issues.

Why is mobile data slow at night?

Many people use the network in the evening, causing congestion.

Ammar Aslam
Ammar writes clear, practical tech guides that help everyday users fix problems, stay safe online and get more from their devices.