When trying to add an endpoint to Pipelines through a proxy, an error will occur if the proxy uses a "Reserved/Local" IP address.
Example "Reserved/Local" IP ranges:
localhost/8
0.0.0.0/8
127.0.0.0/8
10.0.0.0/8
...
Aria Automation 8.x
These IP ranges are blocked by the CodeStream service to prevent any malicious user from pinging localhost or other Internal IP addresses and enumerating the open ports.
Use a direct connection to the endpoint rather than using a proxy with an IP address in one of the above listed ranges.