1. Network Problems: The Most Common Cause

A mobile network connection is essential to make phone calls. Without signal, no calls can go through.

Check Signal Strength

Look at the top of your screen: you should see bars indicating signal strength.
If no bars appear or you see messages like “No Service,” “Network Unavailable,” or “Emergency Calls Only,” your phone is not properly connected.

Easy Solutions

• Move closer to a window or go outside.

• Avoid thick walls and basements.

• Turn Airplane Mode on for 30 seconds, then turn it off.

• Restart your phone.

These simple steps often allow your phone to reconnect automatically to the mobile network.

2. Incorrect Phone Settings Blocking Calls

Some settings can block outgoing calls without you realizing it.

Check Airplane Mode

Airplane mode disables all connections. Make sure it is turned off.

Check Call Blocking Settings

In your call settings, make sure that:

• Outgoing call blocking is disabled.

• Parental controls or work profiles are not restricting calls.

Check Network Selection

Your phone should be set to automatic network selection.
An incorrect manual network selection can prevent calls.

Restart the Phone

A simple restart often fixes temporary system bugs.

3. Faulty or Incorrectly Inserted SIM Card

The SIM card identifies your phone line. Without it, calls are impossible.

What to Check

• Turn off your phone.

• Remove the SIM card.

• Gently clean it with a dry cloth.

• Reinsert it correctly.

• Restart your phone.

Test the SIM Card

If possible, insert your SIM card into another phone:

• If calls work → your phone may have a hardware issue.

• If calls do not work → the SIM card is likely faulty.

In this case, your mobile carrier can usually replace the SIM card for free.

4. Mobile Plan, Line Suspension, or Unpaid Bills

A blocked mobile plan is a very common reason why calls fail.

Possible Situations

• Unpaid bill.

• Data or call limit exceeded.

• Voluntary plan suspension.

• Administrative issue with the carrier.

Solutions

• Log into your customer account.

• Check your line status.

• Contact customer support.

In most cases, service is restored immediately after payment or verification.

5. Software Bug, Update Issue, or System Problem

Some phones may experience call issues after a system update.

Effective Solutions

• Restart the phone.

• Install pending system updates.

• Reset network settings.

Warning: Do not confuse this with a full factory reset, which erases all personal data.

6. Temporary Mobile Carrier Outage

Mobile carriers may occasionally experience local or national outages.

How to Check

• Try making a call from another phone using the same carrier.

• Check your carrier’s website or mobile app.

• Wait a few hours.

In this case, no action is required.

Conclusion

A smartphone that restarts by itself does not necessarily mean a serious hardware failure. In most cases, the issue comes from:

• A worn-out battery

• Overheating

• A buggy app

• Insufficient storage space

By following these simple tips, you can often solve the problem quickly and avoid expensive repairs. If the restarts continue, a professional diagnosis can identify a possible hardware issue.

For more practical guides, simple tutorials, and beginner-friendly tips, visit Premiers Clics, the reference website for learning computers and smartphones step by step.

Summary Table of Causes and Solutions

Thibaut Mathieu