UE4: ProcessReady fails with "An AWS service call has failed. See the root cause error for more information."

I’m seeing the following error message: “An AWS service call has failed.See the root cause error for more information.” after calling ProcessReady from a server executable in an EC2 instance.

The server succeeds using the GameLiftLocal environment - so I’m not entirely certain what could be causing the issue or which direction to proceed in. The only API call I’m making before this is InitSDK, which succeeds.

Any help or hints would be greatly appreciated.

Looks like I was running into a failure case described in this post: https://forums.awsgametech.com/t/ue4-dedicated-server-started-but-did-not-call-initsdk/2880/1

Unreal uses a proxy executable to launch. GameLift looks for the proxy PID and falls down.