After you are sure the backup is done, you are allowed to restore the viber chat.
But the downside is that you are not allowed to restore Viber backups to your phone via the zipped files.
Run iMyFone D-Back and choose " Recover from iOS Device".
How to Leave a Viber Group? Does anyone know any way to recover Viber messages on iPhone? It looks great in doing so, for it also helps us free up mobile space.
And in the lower part is the backup options.