...
*.callpotential.com (needed for anything CP to work)
*.newrelic.com (server monitoring software, site will experience script errors if this isn't whitelisted)
*.fastly.net (used by newrelic)
*.livechatinc.com (allows access to our chat support)
*.infusionsoft.com (allows access to forms on our web site)
*.twilio.com (our telco provider)
*.bootstrapcdn.com (used by the thin client)
*maps.googleapis.com
*google-content.com
sendgrid.com
sendgrid.net
sendgrid.me
sendgrid.info
...