homestead box update SSH issue

$  homestead up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'laravel/homestead' is up to date...
==> default: There was a problem while downloading the metadata for your box
==> default: to check for updates. This is not an error, since it is usually due
==> default: to temporary network problems. This is just a warning. The problem
==> default: encountered was:
==> default:
==> default: SSL certificate problem: unable to get local issuer certificate
==> default: More details here: http://curl.haxx.se/docs/sslcerts.html
==> default:
==> default: curl performs SSL certificate verification by default, using a "bundle"
==> default:  of Certificate Authority (CA) public keys (CA certs). If the default
==> default:  bundle file isn't adequate, you can specify an alternate file
==> default:  using the --cacert option.
==> default: If this HTTPS server uses a certificate signed by a CA represented in
==> default:  the bundle, the certificate verification probably failed due to a
==> default:  problem with the certificate (it might be expired, or the name might
==> default:  not match the domain name in the URL).
==> default: If you'd like to turn off curl's verification of the certificate, use
==> default:  the -k (or --insecure) option.
==> default:
==> default: If you want to check for box updates, verify your network connection
==> default: is valid and try again.

I'm having exactly this same problem. I was able to get over this same error with the "vagrant box add" command, but now I'm stuck at "homestead up"