If Viber is not working, the issue is usually one of four things: a weak internet connection, an outdated app, missing permissions, or a temporary service problem. In most cases, you can fix it by checking your network, restarting the app and device, updating Viber, and reviewing login, notification, and sync settings.

Start with the fastest fixes

Before changing advanced settings, try the basics. These steps solve a lot of Viber app error and connection issue cases in just a few minutes.

Switch between Wi-Fi and mobile data.
Turn airplane mode on for a few seconds, then off again.
Force close Viber and open it again.
Restart your phone, tablet, or computer.
Check whether other apps can access the internet.
See if Viber works on another device or network.

If the app still fails after that, move to the problem-specific fixes below.

Why Viber stops working

Symptom	Likely cause	What to try first
Messages will not send	Network problem or blocked data access	Check Wi-Fi, mobile data, VPN, and battery restrictions
Login failure	Wrong phone number, SMS delay, or account verification issue	Confirm your number and request a new code
Notifications do not arrive	Muted alerts, system permissions, or background limits	Review app and device notification settings
Chats do not sync	Cloud backup issue, device mismatch, or outdated app	Update Viber and verify the same account on all devices
App keeps crashing	Corrupted cache or incompatible version	Clear cache, then reinstall if needed

How to fix Viber connection errors

1. Check the internet connection

If Viber says it cannot connect, test your network first. Open a browser or another messaging app and see whether they load normally. If they do not, the problem is not Viber alone.

Switch from Wi-Fi to mobile data, or the other way around.
Restart your router if the problem happens on home Wi-Fi.
Move closer to the router if the signal is weak.
Ask your carrier if mobile data is restricted on your plan.

2. Turn off VPN, proxy, or private DNS

Some networks block messaging traffic or route it through unstable servers. If you use a VPN, proxy, or private DNS, disable it temporarily and try Viber again.

3. Allow background data and battery access

On Android and iPhone, system settings can limit apps that run in the background. That can stop Viber from connecting properly, especially when the screen is off.

Allow mobile data and Wi-Fi access for Viber.
Turn off battery optimization for the app if it is being restricted.
Make sure background app refresh is enabled on iPhone.

4. Update the app

An outdated version can cause connection errors and unexpected app error messages. Install the latest release from the official Viber Download page if you need to reinstall or refresh the app. If you want general product updates and practical tips, the Viber Blog is also useful.

How to fix Viber login failure

Login problems usually happen during phone number verification. The fix is often simple, but you need to check each step carefully.

Enter the correct phone number with the right country code.
Make sure your SIM card can receive SMS or calls.
Wait a few minutes before requesting another code if the first one does not arrive.
Check whether the device date and time are set automatically.
Remove any old Viber session on another device if the account is already active elsewhere.

If you still cannot log in, uninstall Viber, restart the device, and sign in again with a fresh install. This often clears a broken verification state.

How to fix notification issues

When Viber notifications stop showing up, the app may still be working in the background, but the alerts are blocked somewhere between the app and the operating system.

How do I fix Viber not working?

Open your phone settings and confirm that Viber notifications are enabled.
Check that chats are not muted inside the app.
Review Focus mode, Do Not Disturb, or Sleep mode settings.
Allow sound, banners, and lock-screen alerts if you want visible notifications.
Make sure the app is not being restricted by battery saver mode.

If notifications are delayed rather than missing, the cause is often background data limits or a weak connection. Fixing the connection issue usually improves alerts as well.

How to fix sync issues

Sync issues show up when messages appear on one device but not another, or when chat history seems incomplete. The best approach is to confirm that every device is using the same account and the latest app version.

Update Viber on every device you use.
Sign in with the same phone number on each connected device.
Check whether chat backup is enabled before changing devices.
Let the app finish syncing before closing it or switching accounts.
Clear cache if the app shows old or duplicated messages.

For users who depend on the Viber app for daily communication, sync issues are often a sign that one device is running an older build or has limited background access.

When to clear cache or reinstall Viber

Clearing cache is a good middle step when Viber opens but behaves strangely. It can remove temporary files without deleting your account. Reinstalling is better when the app keeps crashing, refuses to connect, or still shows the same problem after updates.

Clear cache: use this for minor glitches, slow loading, or repeated message refresh problems.
Reinstall: use this if the app is damaged, stuck on login, or has a stubborn connection issue.
Back up first: if your chat history matters, confirm backup or export options before uninstalling.

The rule of thumb is simple: if Viber works on one network but not another, think connection. If it fails everywhere, look at the app, the account, or the device settings.

Step-by-step checklist

Check whether the internet works outside Viber.
Restart the app and the device.
Disable VPN, proxy, or private DNS.
Update Viber to the latest version.
Review login, notification, and background access settings.
Clear cache if the app is sluggish or unstable.
Reinstall only if the earlier steps do not help.

Conclusion

Most cases of Viber not working come down to a network problem, a permission setting, or an outdated install. Start simple, test one change at a time, and avoid reinstalling until you have checked the connection, login, notification, and sync basics. That approach saves time and usually gets Viber back to normal quickly.

FAQ

Why does Viber say no connection when my internet works?

This usually means Viber is being blocked by VPN settings, battery restrictions, or a temporary service issue. Try another network, restart the app, and update Viber.

Why can I not log in to Viber with my phone number?

Most login failure problems come from the wrong number format, delayed verification codes, or a SIM card that cannot receive SMS. Check the country code and request a new code.

How do I fix Viber notifications not showing?

Turn on notifications in both the app and your phone settings, then check Do Not Disturb, Focus mode, and battery saver restrictions.

Why are my Viber messages not syncing across devices?

Sync problems usually happen when one device is outdated or signed in differently. Update the app and confirm that every device uses the same account.

Should I reinstall Viber if nothing else works?

Yes, but treat it as a last step. Reinstalling often fixes a stubborn app error, especially when cache clearing and updates do not help.