If you've configured your Salesforce to use "IP Whitelisting" (meaning that only certain computers or computer networks can access your Salesforce instance), then you need to add InsightSquared to your whitelist.  These are the IP addresses to use (technically, they're IP subnets, in case you run across that term in Salesforce's documentation):

• 173.236.62.0/24

If you need an IP range, use the following:

• 173.236.62.0 to 173.236.62.255