SNWeb can fail to load for a few different reasons.

School Network Firewall

If you are trying to launch SNWeb using internet on a school campus then specific URLs must be whitelisted by the school IT department.  

The relevant URLs are listed here:

SNWeb URLs Whitelist 

Comcast Xfinity ISP

If you are trying to launch SNWeb using internet provided by Comcast Xfinity then you need to disable the protected browsing security feature.  

The process for disabling Comcast Xfinity protected browsing is outlined here:

How To Disable Comcast Xfinity Protected Browsing

Cox Cable ISP

If you are trying to launch SNWeb using internet provided by Cox Cable then you need to disable the advanced security features.  

The process for disabling Cox Cable advanced security is outlined here:

How To Disable Cox Cable Advanced Security Features

Malwarebytes Browser Extension

The Malwarebytes browser extension has also been reported to interfere with SNWeb loading.

If further assistance is required please submit a ticket.