Unable to delete a contact from Contact List in Android phone Phone: Nexus 5x
Operating System: Android 7.0

When I try to delete a contact in contact list of phone it displays the error message:

Contacts from your read-only accounts cannot be deleted, but they can be hidden.
Cancel Hide


When I see the details of the contact, I cannot see the number but I can see it in the Whatsapp contact details.
Go to your phone's System settings→Accounts→(select your account), then turn off Contacts sync.

After that try to delete the contacts from the contacts app.