Some Microsoft services including Azure Active Directory, the Azure Bot Service, and Visual Studio Team Services are down, apparently stemming from a cooling problem in a South Central US datacenter. The VSTS Services team blog has posted this:
We continue to investigate issues in our services impacting all regions. The underlying issue seems to be a datacenter cooling outage in South Central US which is impacting all services in a specific part of the datacenter.
Engineers have isolated an issue with cooling in one part of the data center, which caused a localized spike in temperature, as the preliminary root-cause, which has now been mitigated. Automated data center procedures to ensure data and hardware integrity went into effect when temperatures hit a specified threshold and critical hardware entered a structured power down process. Engineers are now in the process of restoring power to affected devices as part of the ongoing mitigation process.
As is the case with outages like these, the downstream effects of heightened stress on the systems sometimes takes longer to resolve than the issue itself, and it may be a while before everything is back up and running.