How to Troubleshoot a Phone That Cannot Make Calls

A phone that cannot make calls can fail for several reasons. You may have no network coverage, insufficient airtime, a faulty SIM card, incorrect settings or a problem with the phone itself. Sometimes the call connects briefly and drops; in other cases, you may see messages such as “Not registered on network”, “Emergency calls only” or “Call ended”.

Before assuming that the phone is damaged, work through the checks below. They apply to most Android phones and iPhones, although menu names may differ slightly. If you are in Nigeria, also consider whether the issue affects only one mobile network or several networks in your area.

Start with the simple checks

First, look at the signal indicator at the top of your screen. If there are no bars, the phone may be outside network coverage or experiencing a temporary network problem. Move outdoors or to a different location and try again.

Also check the following:

• Confirm that Airplane Mode is turned off.
• Make sure the phone is not switched to Do Not Disturb or a call-blocking mode that affects outgoing calls.
• Check that the correct SIM is selected if your phone has two SIM cards.
• Confirm that the number you are calling is correctly entered, including the country code where necessary.
• Restart the phone and try the call again.

A restart can reconnect the phone to the mobile network and clear a temporary software or registration problem.

Check airtime and account status

Insufficient airtime is one of the most common reasons a normal mobile call will not go through. Use your network provider’s official airtime-checking method, such as its USSD service or mobile app, to confirm your balance.

If you recently recharged, confirm that the recharge was successful. A failed transaction, an incorrect recharge PIN or a delayed account update may leave your balance unchanged. If money was deducted but the airtime did not arrive, keep the transaction reference and contact the provider through its official customer-care channel.

Some lines may also be restricted because of account problems, an inactive SIM or registration-related issues. Do not share your PIN, one-time password or full account credentials with anyone claiming to be customer support.

Turn Airplane Mode on and off

Airplane Mode disconnects the phone from mobile networks. It is useful during flights, but accidentally enabling it will prevent ordinary calls.

1. Open the quick settings panel on Android or Control Centre on iPhone.
2. Tap the Airplane Mode icon to turn it on.
3. Wait about 10 seconds.
4. Turn it off and wait for the network bars to return.
5. Try making the call again.

This forces the phone to search for available mobile networks again.

Check the SIM card

A poorly seated, damaged or inactive SIM card can stop outgoing calls. Switch off the phone, remove the SIM carefully and check for visible damage, dirt or bending. Reinsert it correctly and turn the phone back on.

If the phone displays “No SIM”, “SIM not detected” or “Emergency calls only”, test the card in another compatible phone if one is available. You can also test a working SIM in your phone.

These tests help identify the source:

• If your SIM fails in another phone, the SIM or mobile account may be the problem.
• If another working SIM also fails in your phone, the phone or its SIM tray may be faulty.
• If your SIM works elsewhere but not in your phone, check the phone’s network settings or seek technical assistance.

Do not cut a SIM card yourself unless you are certain it will fit safely. A network provider can replace a damaged SIM while retaining the number, subject to its identification and account procedures.

Check network selection and preferred network type

Incorrect network settings can prevent a phone from registering properly. Open the mobile-network settings and make sure network selection is set to automatic. Manually choosing an unavailable network can leave the phone disconnected.

On many Android phones, this option is under Settings > Network and internet or Settings > Connections > Mobile networks. On an iPhone, look under Settings > Mobile Service or Settings > Cellular, then check network-selection options.

You may also see a setting for preferred network type, such as 4G, 3G or 2G. If calls stopped after changing this setting, return it to an automatic option recommended by your network provider. The exact options depend on the phone, SIM and network.

Look for call barring, fixed dialling or blocked numbers

Call-barring settings can prevent outgoing calls. This may happen after a setting was changed accidentally or after a phone was restored from a backup. Check the Phone app settings for options such as:

• Call barring
• Fixed Dialling Numbers
• Outgoing-call restrictions
• Blocked contacts or numbers

Call blocking usually affects selected numbers, while call barring may affect all outgoing calls. If a security code is requested and you do not know it, do not repeatedly guess. Contact your network provider through an official channel.

Reset network settings

If the phone still cannot make calls, resetting network settings may solve corrupted connection information. This does not normally delete your photos, documents or installed apps, but it can remove saved Wi-Fi networks, Bluetooth pairings and some mobile preferences.

On Android, search Settings for Reset network settings. On iPhone, go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. Read the warning before confirming, then restart the phone and test the call.

Before doing this, make sure you know the passwords for important Wi-Fi networks because they may need to be entered again.

Install software updates

Outdated phone software can sometimes cause network or calling problems, especially after a network provider changes its technical requirements. Connect to Wi-Fi, charge the phone and check for available system updates.

Only install updates through the phone’s built-in settings. Avoid unknown websites or messages offering “network repair” applications, as these may contain malware or try to obtain your personal information.

Identify whether the problem is local or widespread

Ask someone using the same network whether they can make calls from the same location. If several people are affected, the issue may be a temporary network outage or weak coverage. Move to another area and try again later.

If calls work in one location but not another, the phone may be functioning normally and the main issue is coverage. Buildings, underground spaces, thick walls and remote areas can weaken the signal.

When to contact your network provider or a technician

Contact your network provider when your SIM is not registering, your line may be restricted, airtime is missing after payment or the problem continues in different locations. Have your phone number, recent transaction details and a description of the error ready, but do not disclose your PIN or OTP.

Seek a qualified phone technician if the device was dropped, exposed to water, has a damaged SIM tray or cannot detect any SIM card. Avoid opening the phone yourself if you may still need warranty or professional support.

If you need urgent help and ordinary calls are unavailable, try another phone or available emergency contact method. Emergency calling availability can depend on the device, network and location, so do not rely on a phone showing “Emergency calls only” without confirming that a call can actually connect.

A quick decision guide

What you notice	Likely area to check
No signal or “Emergency calls only”	Coverage, Airplane Mode, SIM registration or network outage
“No SIM” or “SIM not detected”	SIM placement, SIM damage or phone SIM tray
Call fails immediately but signal is present	Airtime, call barring, account restriction or network settings
Only one number cannot be reached	Incorrect number, blocked contact or a problem on the other person’s line
Calls fail after a fall or water exposure	Possible hardware damage

The fastest solution is usually to check signal, airtime, Airplane Mode and SIM status before changing advanced settings. If those checks do not help, test the SIM in another phone and contact the network provider. This separates a mobile-account problem from a phone fault and helps you avoid paying for repairs you may not need.