Troubleshooting

App Web Page Shows upstream request timeout

If you get a blank screen showing the message upstream request timeout on your app after running cpflow open -a my-app-name, check out the application logs. Your image has been promoted and your app crashing when starting.

502 Bad Gateway with "protocol error" (Rails + Thruster)

If a Rails app fronted by Thruster returns 502 Bad Gateway with a "protocol error" message, the workload port is likely set to protocol: http2.

Thruster accepts HTTP/1.1 connections from the load balancer, so the workload port must be protocol: http. Control Plane's load balancer still serves HTTP/2 to end users.

See Thruster HTTP/2 Proxy on Control Plane for the full configuration and debugging commands.