JupyterLab in Binder stopped working

[mwouts]

The binder link https://mybinder.org/v2/gh/binder-examples/jupyterlab/master?urlpath=lab/tree/index.ipynb (in this repo) fails to load.

I see a similar issue on Jupytext (mwouts/jupytext#957) - only the link to the "Jupyter Notebook" interface works.

For this repo, the binder logs are the following:

Found built image, launching...
Launching server...
Server requested
Failed to connect to event stream

In the case of the Jupytext binder link, we get a different error (404).

This might not be the proper repository to report this issue, but you might know better than I do how to forward this issue to the people working on JupyterLab in Binder?