The error `websocket: bad handshake` is often the result of starting the quay-builder container before configuring the Quay Enterprise container to accept websocket traffic.
Ensure that Docker Build Support has been enabled in your configuration:
You can also ensure that this is enabled by looking for the parameter
FEATURE_BUILD_SUPPORT: in the config.yaml. It should have a value of
$ cat config/config.yaml | grep -i build_support FEATURE_BUILD_SUPPORT: true
Then start your quay-builder container following the instructions: