It is not currently possible for developers to add new apps to the Windows Phone Marketplace. Microsoft has to upload new apps temporarily discontinued due to a bug in the Store. There are problems with the certificates of the Marketplace.
Users who only recently added or updated apps try to install or update their Windows Phone device currently running against error messages. There is a problem with the digital certificates that sign the apps, this is one of the security measures Microsoft has taken to verify the legitimacy of apps. By refusing the problem Windows Phone devices to recently added or updated apps to install. The phones probably think the app is not legitimate or that the certificate is incorrect. Microsoft has already announced that it is busy with a temporary solution and has the possibility to add new apps or apps to update discontinued. Microsoft now been established that the bug only applies to devices that are upgraded to Windows Mobile 7.5 and not phones that are shipped from the factory with Windows Mobile 7.5. also let Microsoft know that only a small percentage of the 100,000 aps in the Windows Marketplace affected by this bug. The painful thing is that among that small percentage is also very popular apps are as WhatsApp, Translator for Bing and the New York Times app.All apps that have recently been updated with a new version. Microsoft expects short-term solution to roll out, but until then must use an error message when installing or updating an app have patience.