Vagrant up crashes but finish setup and exists

[federicosan]

Well, it finishes but at the same time crash with this error

default: Failed to open terminal.debconf: whiptail output the above errors, giving up!
default: dpkg: error processing package grub-pc (--configure):
default: subprocess installed post-installation script returned error exit status 255
default: Errors were encountered while processing:
default: grub-pc
default: E
default: :
default: Sub-process /usr/bin/dpkg returned an error code (1)
default: Installation succeeded
default: Now run vagrant ssh

I don't know if this error is ok, it will let me get into ssh ok but what is this error, I don't know.