SERVER_PROCESS_SDK_INITIALIZATION_TIMEOUT

The SERVER_PROCESS_SDK_INITIALIZATION_TIMEOUT error indicates that your game server process failed to call the InitSDK() method within the expected timeframe (5 minutes). This is a common issue when setting up Amazon GameLift fleets.

Based on similar issues with the GameLift SDK 5.1.2, there are several potential causes and solutions to explore:

1. For .NET/C# implementations on Linux, setting InvariantGlobalization to true has resolved this issue for some users. This configuration affects how .NET handles globalization in Linux environments.

2. Verify that your launch path is correct for the Linux operating system. The error could indicate that the server process is starting but failing to properly initialize the SDK.

3. Check that your build's target architecture matches your instance type. If you're using x64 instances, ensure your build targets linux-x64, or if using Graviton instances (ARM-based), ensure you're targeting linux-arm64.

4. Ensure you're not passing server parameters to InitSDK() when deploying to a managed EC2 fleet (these are only needed for Anywhere fleets).

5. Review your game session logs to identify any errors occurring before the SDK initialization attempt. You may need to access these logs through the GameLift console or using the pre-signed URL provided in the event message.

6. Verify that your server process has the necessary permissions to execute and that all required dependencies are included in your build.

7. If you're using the WebSocket connection in the GameLift SDK, ensure your network configuration allows for this connection to be established.

Since you're using Unreal Engine 5.5.4 with the GameLift SDK 5.1.2, also verify that there are no compatibility issues between this specific Unreal version and the SDK version you're using.
Sources
Event - Amazon GameLift Servers
Event (AWS SDK for Java - 2.21.29)
Gamelift C# sdk 5.1.2 initSDK errors when trying to create a fleet in Amazon Linux 2023 using On Demand Ec2 c5.large instances | AWS re:Post
What is GameLiftWebSocket? | AWS re:Post