I successfully deployed a simple Voila dashboard using [Google Cloud Run for Anthos](https://cloud.google.com/anthos/run). However, since I created the deployment using a GitLab CI pipeline, by default the service was assigned a long and obscure domain name (e.g. <http://sudoku.dashboards-19751688-sudoku.k8s.proteinsolver.org/>).

I followed the instructions in [mapping custom domains](https://cloud.google.com/run/docs/mapping-custom-domains) to map a shorter custom domain to the service described above (e.g <http://sudoku.k8s.proteinsolver.org>). However, while the static assets load fine from this new custom domain, the interactive dashboard does not load, and the javascript console is populated with errors:

```js
default.js:64 WebSocket connection to 'wss://sudoku.k8s.proteinsolver.org/api/kernels/5bcab8b9-11d5-4de0-8a64-399e35258aa1/channels?session_id=7a0eed38-77bb-40e8-ad77-d05632b5fa1b' failed: Error during WebSocket handshake: Unexpected response code: 503
_createSocket @ scheduler.production.min.js:10
[...]

```

Is there a way to get web sockets to work with custom domains? Am I doing something wrong?