Is Microsoft Teams down?
Nope
As of 18:00:42 UTC on 2021-08-03, according to Microsoft nothing is going on, it's all good for now.
The last update was 4 days ago:
2021-07-30 14:07:33: "We're investigating an issue in which users may be unable to connect to Power Apps. Additional information will be provided in the admin center under MO274372."
Followup:
Jul 30, 16:37 PST: "After a period of monitoring, we've confirmed that the issue is fully mitigated and all previously affected connections have been restored. Full details about the issue can be found in your admin portal under MO274372."
+ more details