Yesterday morning Microsoft adCenter, Bing's search marketing product, went offline for a period of time. Microsoft confirmed the outage in the Microsoft Advertising Forum yesterday and this morning confirmed it was fixed.
The first report came yesterday morning, Monday, December 27th at 7:30AM. Microsoft then confirmed the issue about 20 minutes later. This morning, almost 24 hours after that report, Microsoft confirmed it was fixed.
Paul K. from the Microsoft team said:
Currently the issue has been resolved. If you are experiencing anymore issues please contact support with screenshots and description of what is occurring. We will be glad to investigate further.
Exactly what caused the issue is unknown. I doubt it was related to the big winter storm we had here Sunday and Monday but hey - you never know.
Forum discussion at Microsoft Advertising Forum.