I have created a windows store app. I included ads from Microsoft pubCenter. It has been published today and I downloaded it on my laptop and a friend's. In both occasions the ads only show Microsoft advertising ads. Nothing more, nothing less. I added a simple adcontrol line in my xaml as advised and in application id I inserted what was given in pubcenter and same in ad-unit. Is there something wrong with Microsoft Ads?
Microsoft Ads use an algorithm designed for targeted advertising based off of information they receive from the users of a given application. Sometimes the advertising targets a specific user, sometimes it targets a specific app's demographic.
There are quite a few possible reasons that your app is displaying primarily Microsoft ads. It could be that you and your friend are both prime targets for Microsoft products. It could be that your app's demographic or genre is targeted for Microsoft ads.
It could also be that Microsoft's own ads are the default (likely, I'd think). It may take a bit for the demographics information to be received by Microsoft ads, or any other numerous reasons that the default ads are currently being displayed.
Basically, as of right now, there is nothing pointing at this being your fault. With more datapoints over more time, we could possibly begin to eliminate unlikely causes (such as sync time on a specific device).
I don't think you have anything to worry about now. If your ad revenue is particularly low or otherwise anomalous, then maybe there is some need for concern, but until there is some more information, we can only speculate.