Is your phone showing 4G or 5G but mobile data is not working? Or has your phone suddenly switched to 3G, E, H+, or no mobile network at all? Mobile data problems can prevent websites, apps, maps, social media, and other online services from working when you are away from WiFi.

The problem can be caused by incorrect mobile-data settings, a weak network signal, an inactive SIM, incorrect APN settings, carrier restrictions, network congestion, or a temporary software issue.

Fortunately, many 4G and 5G mobile data problems can be fixed with a few simple troubleshooting steps.

This guide explains how to fix 4G/5G not working on your phone and restore mobile internet on Android and iPhone devices.

Why Is 4G or 5G Not Working on My Phone?

Several things can prevent mobile data from working correctly.

Common causes include:

• Mobile data is turned off
• Airplane Mode is enabled
• Weak network coverage
• Incorrect preferred network type
• SIM card problems
• Incorrect APN settings
• Expired or inactive mobile-data plan
• Carrier outage
• Network congestion
• Roaming restrictions
• Data limit reached
• Incorrect network settings
• VPN or software interference
• Outdated phone software
• SIM or phone hardware problems

Quick Diagnosis

How to Fix 4G/5G Not Working on Your Phone

1. Turn Mobile Data On

Start by checking whether mobile data is enabled.

On most Android phones, swipe down from the top of the screen and make sure Mobile Data is turned on.

On iPhone, go to:

Settings → Cellular/Mobile Data

Make sure cellular data is enabled.

If you use multiple SIMs, also confirm that the correct SIM is selected for mobile data.

2. Turn Airplane Mode On and Off

Airplane Mode can quickly reset your phone’s wireless connections.

Turn Airplane Mode on and wait about 10–15 seconds.

Then turn it off.

Wait for the mobile network to reconnect and check whether 4G or 5G appears.

This can resolve temporary network-registration problems.

3. Restart Your Phone

A simple restart can clear temporary network and software glitches.

Turn your phone off completely, wait a few seconds, and turn it back on.

After the phone reconnects to the carrier network, test mobile data.

If 4G/5G was working normally earlier and suddenly stopped, restarting is one of the easiest fixes to try.

4. Check Your Network Signal

Look at the signal indicator on your phone.

If you have only one bar or no signal, mobile data may be slow or unavailable.

Move outdoors or to an area with better coverage and test again.

Buildings, underground locations, hills, and other physical obstacles can affect cellular signals.

5. Check Your Mobile Data Plan

Your data connection may stop working if your mobile-data allowance has been used up or your plan has expired.

Check your carrier’s official app, website, or account information.

Also verify that your SIM is active and that there are no account restrictions.

If your plan has expired, changing phone settings will not restore mobile data until the account issue is resolved.

6. Check the Preferred Network Type

Your phone may be configured to use an unsuitable network mode.

Look under your mobile network settings for an option such as:

Preferred network type or Voice & Data

Depending on your device and carrier, available choices may include:

• 5G
• 4G/LTE
• 3G
• Automatic

Choose the automatic or carrier-recommended option.

If 5G is unreliable, temporarily selecting 4G/LTE can help determine whether the problem is specific to 5G.

7. Test 4G Instead of 5G

If your phone supports 5G but mobile data is not working correctly, temporarily switch to 4G/LTE.

If 4G works normally while 5G does not, the issue may involve:

• 5G coverage
• Carrier support
• Phone compatibility
• Network configuration
• Local network conditions

You can continue using 4G while investigating the 5G problem.

8. Check Your SIM Card

A poorly seated or damaged SIM card can cause mobile-network problems.

If your phone uses a physical SIM, turn the phone off if required by your device instructions and carefully remove the SIM.

Check for visible damage and make sure it is positioned correctly in the tray.

Reinsert it and restart the phone.

Do not force the SIM tray or card.

9. Try the SIM in Another Compatible Phone

If possible, test the SIM in another compatible, unlocked phone.

If mobile data does not work there either, the issue may be related to the SIM or carrier account.

If the SIM works normally in another phone, the original phone’s settings or hardware may be responsible.

10. Check APN Settings

APN stands for Access Point Name.

Your phone uses APN settings to connect to your carrier’s mobile-data network.

An incorrect APN can cause mobile data to stop working even when you have good signal strength.

Open your mobile-network settings and check the APN.

Use the APN information provided by your carrier.

Do not copy APN settings from random websites because incorrect values can cause additional connection problems.

11. Reset APN Settings to Default

If you previously changed APN settings, restoring the default configuration may help.

Look for an option such as:

Mobile Network → Access Point Names → Reset to Default

The exact location depends on your phone and carrier.

After resetting the APN, restart mobile data and test the connection.

12. Check Data Usage and Data Limits

Your phone may have a built-in data limit that prevents mobile data from working after a certain amount of usage.

Open your phone’s mobile-data settings and check:

• Data usage
• Billing cycle
• Data warning
• Data limit
• Background data restrictions

If a data limit has been reached, adjust it only if you intentionally set the limit and your carrier plan allows additional usage.

13. Disable Data Saver Temporarily

Data Saver or Low Data Mode can restrict background network activity.

On Android, check the Data Saver setting.

On iPhone, check Low Data Mode for the relevant cellular connection.

Temporarily disable the feature and test mobile data.

If the problem disappears, review which apps are being restricted.

14. Disable VPN Temporarily

A VPN can sometimes interfere with internet access.

If you use a VPN, disconnect it temporarily and test a website or app.

If mobile data starts working after disconnecting the VPN, review the VPN application and its connection settings.

Do not permanently disable security tools unless you understand the consequences.

15. Check Data Roaming When Traveling

If you are outside your carrier’s normal service area or traveling internationally, mobile data may require roaming.

Check your carrier’s roaming policy first because roaming charges may apply.

If your plan supports roaming, enable data roaming when appropriate.

If you are not traveling, leave data roaming disabled unless your carrier specifically requires it.

16. Reset Network Settings

If your mobile-data configuration has become corrupted, resetting network settings may help.

This option can remove saved:

• WiFi networks
• Bluetooth connections
• Cellular/network configurations
• Other network preferences

Because the exact reset behavior varies by phone, read the confirmation screen carefully before proceeding.

After the reset, reconnect to WiFi and configure your mobile network again if necessary.

17. Install Phone Software Updates

Outdated phone software can sometimes cause connectivity or carrier-compatibility problems.

Check your phone’s system-update settings.

Install available updates from the official device manufacturer.

Make sure the phone has enough battery and stable WiFi or another reliable connection if required for the update.

18. Check for a Carrier or Network Outage

Your phone may be working correctly while the carrier network is experiencing an outage.

Check your carrier’s official service-status page, app, or customer support channels.

You can also ask whether there are known network problems in your area.

If many people using the same carrier are experiencing the same issue, changing your phone’s settings may not solve it.

19. Check Whether the Phone Supports the Carrier’s Network

A phone may support 4G or 5G in general but still have compatibility limitations with a particular carrier.

This can happen with:

• Imported phones
• Region-specific models
• Unlocked devices
• Unsupported frequency bands
• Carrier-specific 5G requirements

Check the exact phone model and supported network bands with the device manufacturer and your carrier.

20. Contact Your Carrier or Get Professional Help

If 4G/5G still does not work after troubleshooting, contact your carrier.

Ask them to check:

• SIM status
• Account status
• Mobile-data service
• APN configuration
• Network coverage
• 4G/5G eligibility
• Local outages
• SIM replacement requirements

If the carrier confirms that your account and network are working normally, the phone itself may need professional inspection.

When Should You Get Professional Help?

Contact your carrier or a qualified technician if:

• The SIM does not work in multiple phones.
• Your phone cannot detect the SIM.
• The phone shows no network despite good local coverage.
• Mobile data stopped after physical damage.
• The phone was exposed to water.
• The SIM tray is damaged.
• Network problems remain after a network reset.
• Other wireless functions are also behaving abnormally.
• The carrier confirms that your account and network are working normally.

If your phone has been exposed to water, avoid charging it until it has been properly inspected.

Safety Tips

Keep these precautions in mind:

• Do not force the SIM card into the tray.
• Do not bend or cut a SIM card yourself.
• Use only compatible SIM accessories.
• Do not enter random APN settings from untrusted websites.
• Avoid unofficial firmware or network-modification tools.
• Back up important data before major resets.
• If the phone has liquid damage, do not charge it.
• Use official carrier and manufacturer support for network configuration.

How to Prevent 4G/5G Mobile Data Problems

You can reduce connectivity problems by following a few simple habits:

• Keep your phone software updated.
• Keep your SIM card in good condition.
• Monitor your mobile-data allowance.
• Use the carrier’s recommended APN settings.
• Avoid unnecessary VPN or network modifications.
• Keep your phone’s network settings at their recommended defaults.
• Check carrier coverage before traveling.
• Use a supported 4G/5G phone and SIM.
• Restart your phone if it develops temporary network problems.
• Keep important carrier-account information accessible.

Frequently Asked Questions

Why is my phone showing 4G but the internet is not working?

Your phone may be connected to the cellular network but unable to access mobile data because of an inactive data plan, incorrect APN settings, network restrictions, congestion, or a temporary carrier problem.

Why is 5G not working but 4G works?

5G may not be available in your current location, or your phone, SIM, plan, or carrier account may not support the required 5G service. Test 4G/LTE and check your carrier’s 5G requirements.

Why does mobile data work outside but not inside my house?

Buildings and other obstacles can weaken cellular signals. Try moving near a window or outdoors and compare the signal.

Can a SIM card cause 4G or 5G problems?

Yes. A damaged, inactive, incorrectly provisioned, or improperly seated SIM can prevent mobile data from working.

Will resetting network settings delete my photos?

A network-settings reset normally does not erase personal photos or videos, but it can remove saved WiFi networks, Bluetooth connections, and other network preferences. Always read your phone’s reset confirmation before proceeding.

Why does my phone have signal but no internet?

Signal bars mainly indicate the phone’s connection to the cellular network. They do not guarantee that mobile-data service is working. Check your data plan, APN, network settings, and carrier status.

Can Airplane Mode fix mobile data?

Turning Airplane Mode on briefly and then off can force the phone to reconnect to the cellular network. It can resolve temporary network-registration problems.

Should I use 4G or 5G?

If both are available and working correctly, your carrier and phone may automatically select the appropriate network. If 5G is unstable, testing 4G/LTE can help identify whether the issue is specific to 5G.

Final Words

When 4G or 5G is not working on your phone, the problem can come from simple settings or from the carrier network itself. Start by checking mobile data, Airplane Mode, signal strength, your data plan, and preferred network settings.

If those steps do not help, check the SIM card, APN configuration, data restrictions, VPN, and network settings. Testing the SIM in another compatible phone can also help determine whether the problem is with the SIM or your device.

If the carrier confirms that your account and network are working correctly but mobile data still does not work, professional phone inspection may be necessary.