iPhone Wont Set Up From Back Up

Ive been trying to restore my new iPhone 6 from my iPhone 4s back up. Every time i try i click continue the message "Enter the password to unlock your iPhone Backup" comes up and i don't know what password iTunes is looking for. I've tried the phones password (old and new) the computers password, and removing the password from both iPhones. I've also tried my apple Id password