Why vagrant up dose not offer password input?

box version:centos 2004_01
vagrantfile configration:
node.ssh.username=“root”
node.ssh.password=“root”

The first time when I use vagrant up, the pre version will break and wait for me input password, so i can input the password(above), but the latest version(2004_01) dose not, and warning:

Blockquote
kn1: Warning: Authentication failure. Retrying…

why?