Interactive SAIL expression examples embedded in Appian documentation pages fail to execute. The browser displays the following error message:
The connection is blocked because it was initiated by a public page to connect to devices or servers on your local network.
This issue occurs in networks where the AWS API Gateway endpoint used by the documentation resolves to a private IP address.
Appian documentation pages use an AWS API Gateway endpoint with the domain *.execute-api.us-east-1.amazonaws.com to support execution of SAIL expressions. In enterprise networks AWS service endpoints may resolve to a private IP address. Modern browsers block requests where the originating page is treated as public and the target endpoint resolves to a private or local IP address. This is intentional browser behavior designed to prevent DNS rebinding and local network attacks.
*.execute-api.us-east-1.amazonaws.com
This is a known limitation that affects enterprise networks with private AWS networking configurations. Appian has added an enhancement to the documentation backlog to address this issue (Reference ticket: LCP-49998). No estimated time of availability is currently provided for this enhancement.
Organizations may allow *.execute-api.us-east-1.amazonaws.com domains to resolve using public DNS controls to ensure the page loads properly.
This article applies to all versions of Appian.
Last Reviewed: May 2026