I've experienced this with Slack before where the push notifications come through but opening them fails to load.

I imagine their infrastructure to send push notifications is decoupled from their infrastructure for chat services themselves.

It'd be interesting to know if they have a master switch to disable notifications in times like this where they aren't usable anwyay.

This happens to me almost every day, when there are no incidents/outages. And it's not a network issue, the other apps work fine (e.g. WhatsApp).

I cannot get to slack in my phone or in the browser.

I wonder if this is because I haven't used the phone app in a few days, so I was already logged out, but you and others were still logged in?

Me too. However it won't let me open DMs to certain people.

Same, I still see my colleagues typing but that's it.

Same, but when I go to view the message it hangs.

I too am in this same boat.