Down for me. Using the browser.
Something’s gone awry and we’re having trouble loading your workspace.
Sorry we can’t be more specific – this is one of those cases where we don’t know what’s gone wrong either. A restart of Slack might help, and you can always contact us.
most people IME use the slack app, in which case "restart" makes sense.
In all seriousness, since I'm sure a lot of people don't know this, use SHIFT-CTRL-r. That instructs the browser to reload everything, ignoring cached resources. This can occasionally "restart" a web page that even a reload or loading the URL in the URL bar again is not sufficient for. Slack is one of those things I've seen it work on.
However, SHIFT-CTRL-r isn't enough now.