I can't log in to the dashboard

I'm trying to do my initial login to the dashboard to install Appointments+ and I keep getting this error message:

Your server had a problem connecting to WPMU DEV. Please try again.
If this problem continues, please contact your host and ask:
"Is php on my server properly configured to be able to contact https://premium.wpmudev.org/wdp-un.php with a GET HTTP request via fsockopen or CURL?"

I'm using Biz.nf hosting, is there a different way to install the plug-in system, or is this completely an issue on their end?