A network security device is probably interfering with your session.
Glance works through most network security devices. But some may have a policy that disrupts sessions.
Your guests might not be able to connect or your session might pause or drop unexpectedly — a few seconds or even a few minutes after your guests connect. You might be able to start another session (or your guest might manually reconnect), only to see the new connection fail again in the same manner.
If you or your guest connect through a corporate network and experience any of these symptoms, contact your respective IT department for help resolving the issue.
For best performance, have the IT specialist add a rule that allows outbound TCP/IP connections to destination port 5500 on Glance servers in the domains glance.net and glanceops.net. Alternatively, add the rule for Glance's IP address blocks, as detailed here.