Description

We are experiencing consistent connection failures when running our application via Proton 10.0.4 in an AWS EC2 environment. The issue appears to affect Agora SDK’s ability to establish both UDP and TCP connections required for real-time communication.

Environment

• Proton version: 10.0.4
• Platform: AWS GameLift Stream
• OS: Linux (Proton)
• Instance type: g5.2xlarge (reproducible on any instance type)
• Network setup: Default VPC (fully open)
• Agora SDK version: 4.5.1

Issue Details

• Agora fails to connect to its signaling/media servers.
• Both UDP and TCP transport attempts appear to fail.
• No successful fallback is observed.
• The issue occurs consistently across multiple runs.

Expected Behavior

Agora SDK should successfully establish a connection (UDP preferred, TCP fallback) and allow media streaming.

Actual Behavior

• Connection attempts fail.
• No media streams are established.
• SDK reports network or transport-related errors.

Additional Notes

• The same setup works correctly outside Proton (standard Windows EC2 environment).
• Unable to verify with older Proton versions; the game is only playable starting from 10.0.4.
• EC2 security groups allow outbound traffic (all ports/protocols or at least required Agora ports).
• No apparent firewall restrictions at the OS level.
• If a connection is successfully established, audio transmission works correctly over WebRTC, but video streaming experiences connection drops.
• Video connection may degrade over time, eventually dropping completely mid-call.

Questions

• Are there known networking limitations or regressions in Proton 10.0.4 affecting UDP/TCP?
• Is there any additional configuration required for Proton when running in cloud environments like EC2?
• Are there recommended debugging flags or logs to further diagnose networking issues?

Reproduction Steps

Case 1

1. Launch EC2 instance
2. Install and run application via Proton 10.0.4
3. Initialize Agora SDK
4. Attempt to join a channel
5. Observe connection failure

Case 2

1. Launch EC2 instance
2. Install and run application via Proton 10.0.4
3. Initialize Agora SDK
4. Attempt to join a channel
5. If the channel is joined, wait a few minutes
6. Observe bitrate drop due to video streaming connection breaking (UDP/TCP transport can no longer be re-established)

Possible Related Areas (based on AWS/Agora support)

• Proton networking layer
• UDP socket handling
• NAT traversal / STUN/TURN behavior

Please let me know if additional logs or diagnostics would help.