It’s the funniest thing today. None of the 3 buttons do a damn thing. I couldn’t use Teams properly or Excel or teams web because it’s blocked. I’m in support so user’s start to flag it to me as well. Got in touch with my mate in Sec turns out it’s an automated response from defender flagging its own backend as malicious cloud provider or something like that.

Edit: title, it turns out it’s the Info Sec team who went a bit overboard with the block listing.