iPhone backup through iTunes - WhatsApp chats not restored but...

Hi everyone,

I have a full backup of iPhone 7 that I have successfully restored into iPhone Xs with the exception of the WhatsApp chats. Into the new iPhone Xs I am not able to see my old chats that I know are inside the backup done by iTunes: if I use the free edition of the program "iMyFone D-Port Pro" or similars, I can see all my chats, but yes...to restore I have to buy a license.

What I want to know is if I might have done something wrong, or if I just have to try to restore it again and to hope for the best :-).

Thanks a lot

Bye

Roberto