Ask HN: Microsoft Teams is down for WOW internet users–how's this possible?

I can access Teams on my phone over a cellular connection but not when I'm on my WiFi connection. Other people are reporting similar issues: https://downdetector.com/status/microsoft/

I don't see any updates on the status page on twitter: https://twitter.com/MSFT365Status

How does it work for cellular and other internet providers, but not mine?