I created a vagrant box using vagrant package , uploaded it and released it.
Then I did vagrant init <username>/<box> which created a Vagrantfile. I even appended the box version to the Vagrantfile.
Next I did vagrant up --provider virtualbox. This tries to get the box locally and then when it can't find it, i get the error:
The box you're attempting to add doesn't support the provider
you requested. Please find an alternate box or use an alternate
provider. Double-check your requested provider to verify you didn't
simply misspell it.
If you're adding a box from HashiCorp's Atlas, make sure the box is
released.
I have given virtualbox as the provider and virtual box works fine with other boxes I use.
What I figured was that due to some reason vagrant had got corrupted. So doing a fresh install of vagrant did the trick.