You need to whitelist certain external links along with FogBugz links in your firewall for the FogBugz functionality to work smoothly. These functions include email reception via POP3 or IMAP if you are using FogBugz Mailboxes, the On-Demand service itself, and the other outbound services, like URL Trigger and Webhooks.
This article provides the list of external links and FogBugz links that are to be whitelisted in your firewall.
Please whitelist the following links for FogBugz and Chrome Browser:
External Links for FogBugz
Please whitelist the external links listed below:
External Link for Kiln
For Kiln, please whitelist the following link: