Why Is My SIM Card Not Working

Diagnosing why your network internet has stopped working (Why Is My SIM Card Not Working)

Step	Action	What It Fixes
1	Check your network status	Confirms if issue is network-wide
2	Toggle aeroplane mode on/off	Re-registers SIM on your network
3	Restart your phone	Clears temporary network errors
4	Check your network APN settings	Fixes incorrect data configuration
5	Re-insert SIM card	Fixes poor SIM contact issues
6	Contact your network support	Resolves account or SIM faults

Publishing order: 467 • Cluster 41: FAQ High Search

If your internet connection is slow or mobile data is not working properly, this Why Is My SIM Card Not Working | UK Mobile guide will help you configure everything correctly.

Configuration, data drops, poor signal and general settings for a UK handset are covered.

The basics handle most no-service, slow-data, hotspot, SIM-lock, roaming and APN problems — try those first.

A power cycle generally reconnects the phone; give it roughly 30 seconds afterward.

Verify cellular data and roaming are switched on, matching what the tariff includes.

Ruling out a missing or wrong APN starts with checking mobile internet settings.

📶

Troubleshooting checklist

Work through in sequence — most people are done by step two

Step 1Check APNStep 2Select APNStep 3Toggle flight modeStep 4Restart phoneStep 5Test data

Quick checks before resetting your network APN settings (Why Is My SIM Card Not Working)

Look at the APN profile under Mobile Network or Cellular Data, save, restart, and test browsing, MMS and hotspot.

Internal guides to check next

UK APN Settings Troubleshooting Why Is My Mobile Data Not Working How to Reset APN Settings What Are APN Settings APN Settings Explained What Is eSIM and How It Works How Roaming Works Back to full blog order

Frequently Asked Questions About Why Is My SIM Card Not Working

Why is your network mobile data not working?

your network mobile data may stop working due to an incorrect APN, a temporary network outage, an expired data plan, or a SIM issue. Follow the steps in this guide to identify and fix the cause.

How do I reset my your network APN settings?

On Android: go to Settings → Network → Mobile Networks → Access Point Names, then tap the menu and select 'Reset to default'. On iPhone: go to Settings → General → Transfer or Reset iPhone → Reset → Reset Network Settings.

Does your network have a network outage in my area?

Check your network website or their social media channels for real-time outage information. You can also check third-party sites like Downdetector for user-reported your network outages.

Why does your network show signal but no internet?

If your network shows signal but no internet, the APN settings may be incorrect or missing. Check the APN settings on your device and compare them to the correct your network values in our APN guide.

How long does a your network outage usually last?

Most your network outages are resolved within a few hours. For planned maintenance, your network usually notifies customers in advance. Check your network status page for current updates.