Mongo error when connecting via uri.

I'm using Pritunl. I set up a Mongodb cluster, and I'm trying to connect one of my VPN servers to it.

Here's the error in the logs:

"`ssl_cert_reqs` is not ssl.CERT_NONE and no system " ConfigurationError: `ssl_cert_reqs` is not ssl.CERT_NONE and no system CA certificates could be loaded. `ssl_ca_certs` is required. 

Here is how I'm trying to connect:

mongodb://user:PASSWORD@subnet.domain.com:27017/pritunl?ssl=true 

I've done my fair share of googling and can't seem to find much about this.