Ok go to Settings > Cloud and Accounts > Accounts and make sure WhatsApp is in there and if it is click sync, and if it's not there add WhatsApp to your accounts.
Try this, go to Contacts > Then click the 3 little dots up in the top right hand corner > Mange Contacts > Sync Accounts and in there make sure that WhatsApp is there and switched on.
Im having the same contact problem. None of the above methods worked. WA only picks up 65 out of over 500 contacts. Also tried un- & reinstalling with no luck.
I was having the same contact issue where I was not seeing my contacts on Whatsapp after all above permissions were on and reinstalled a couple times. What I realised was when I downloaded the vcard from google the format the numbers were in was not picking up on the phone (the phone numbers were not in the number field but in the notes field) which is why they were not registering in whatsapp. So I had to copy and past the number into the correct field in order for the contacts to show in whatsapp.
