WebSocket Connection Failed During Workflow Execution

Troubleshooting
1

When clicking Execute to run a workflow, a dialog appears indicating that it could not connect to the server.
In browser developer tools, you may see: “WebSocket connection failed.”

Possible Causes & Solutions

1. WebSocket Ports Blocked

  • Ensure required WebSocket ports are open within your VPC.

  • Verify Security Groups / Network ACLs allow inbound and outbound traffic.

2. Firewall or Security Restrictions

  • Check if any firewall or security agent inside the VPC/VM is blocking WebSocket connections.

  • This includes:

    • OS-level firewall (iptables, ufw)

    • Corporate network restrictions

3. Browser Compatibility

  • Ensure you are using a supported browser version.

  • Older browsers may not support required SockJS/WebSocket protocols.

4. VPN / Antivirus Interference

  • Disable or check:

    • VPN connections

    • Antivirus or endpoint security tools

  • These can sometimes block or inspect WebSocket traffic.

5. Insufficient Memory

  • Ensure at least 16 GB RAM is allocated to Sparkflows.

  • Low memory can cause services (including WebSocket handlers) to fail.

6. Proxy / Network Drops

  • Verify that:

    • No proxy is interrupting WebSocket connections

    • Connection is not being dropped by load balancers or gateways

Reference Documentation

For more details, refer to:
https://docs.sparkflows.io/en/latest/troubleshooting/websockets.html