Hello
If you are having your user to change and you want to keep the VMS then you would have to do some manual work
base boxes are in ~/.vagrant.d
default VMs in Virtualbox are created in ~/VirtualBox VMs
as the path of the home user have have changed, your new user wont have those directories
i would suggest to try to create new VMs using the project file / vagrant up should create a new environment
If you need to copy things from the old VMs, you could login with non-domain user, and extract the data / changes you need
Thanks!
Alvaro.