Vagrant Trellis problem

I know this isn’t specifically a problem with Trellis but more of Vagrant. However, I just want to take chances and see if anyone has ever encountered this problem and probably has a solution for it:

I’ve run vagrant up on Trellis but I always get asked for permission and the console throws error:

An error occurred in the underlying SSH library that Vagrant uses.
The error message is shown below. In many cases, errors from this
library are caused by ssh-agent issues. Try disabling your SSH
agent or removing some keys and try again.
If the problem persists, please report a bug to the net-ssh project.
timeout during server version negotiating

I’m running:
OSX: El Captian
Vagrant: 1.8.1
vagrant-bindfs (0.4.7)
vagrant-hostmanager (1.8.1)
vagrant-notify (0.4.0)
vagrant-omnibus (1.4.1)
vagrant-parallels (1.6.2)
vagrant-share (1.1.5, system)
vagrant-vbguest (0.11.0)
Virtual Box: 5.0.16

So I used a parallels provider instead. Because I couldn’t find a fix for the VirtualBox.