RolandP When a website is offline, like my e-banking, there is redirect to a ‘sorry we are offline’ page
The error page was eventually replaced with a “temporary offline” page, and we did also get a warning in the app that there were issues.
It is annoying. I know a bit of how the whole SBB online platform (and the backed for the app) works, as my employer was involved in it. When you go to the Swiss Pass login site you first hit a reverse proxy, that then forwards your request to a backend. If the backend fails you get an error, often nondescript as the proxy does not really know what is going on..
Having something essential as a single login system fail should not happen. I guess the SBB IT department has some work to do here.