Hi, if you followed instructions from this article, and your contacts still do not show up, please contact Viber tech support on their website and report the issue with Viber on your device.

It worked. Thank you so much.

Hi, Viber App has so many weird bugs, and with each new update they seem to introduce more bugs than fixes :)

Now, the only way to try and fix this on your own is to uninstall Viber and install it back again. Don’t worry, your Group membership and messages will be preserved during this quick adventure (your other chats might not, though… so make a complete backup of text messages to Google Drive if you wish to later bring them back – keep in mind that photos and videos cannot be backed-up to Google Drive, but they will not be deleted from your device’s internal storage, that is, if you do not manually delete them, they will be there even after reinstall). Then, see if the problem is fixed.

If not, then your only hope is to report this issue to Viber devs and hope they’ll fix it eventually.