You entered the correct country code and phone number.

Check the phone number and SIM card - you need to check if the SIM card is valid.

Viber error 'registration can't be completed' Tips for mobile users: Learn how to clear the WhatsApp cache from your iPhone, Samsung, or any other Android phone with this easy step-by-step guide.

If this doesn’t help, repeat the steps but only click on Clear Data instead of Clear Cache, and see if it works. Go to your phone Settings, find App Manager (or however it's called on your phone), and find Viber.

The easiest way to fix this issue is to clear the cache and data. However, many users experience this issue even if the conditions mentioned above are fulfilled. Updating Viber shouldn't be a problem if you have enough memory or are connected to the internet. You can also find more information on securely backing up your Viber data on a computer. Tip: before fixing Viber crashing issue, please backup your Viber data using mobitrans. Now, clear cache and storage to free up some space.Click on the apps & notifications icon.Then check if your phone has a good internet connection.

First, you need to restart your phone and check if you are running the latest version of Viber.

Viber icon display