Need help to determine why some of game sessions in GameLift fleet are running forever.

I'm using Gamelift as dedicated server for my multiplayer game. Everything works well, just one problem: in my game fleet dashboard, sometime for unknow reason, some game session are running forever, doesn't shutdown. Please see my attached screenshot below. I've tried every way I can think to terminated a game session. even I write a script to report game session as unhealthy if the game session is running for more than 2 hours, but it seem doesn't work. Is there anyway I can check what happend for these game session? Or how can I check log to see what's the error? (because the game session does not shutdown so I can't see log). Here is some additional information about my game fleet: Fleet id: fleet-91342684-5597-4fbe-9854-51f4aa1fc0e4 Example a game session that doesn't shutdown: session id: arn:aws:gamelift:ap-southeast-1::gamesession/fleet-91342684-5597-4fbe-9854-51f4aa1fc0e4/669aa29f-eb0d-4f46-b52b-7a456c2a3354 ip: 54.179.179.230 port: 8127 Thank you very much for your help! I've been struggled with this problem for months :D