I mainly use Firefox Nightly for its speed, easy launching PDF Files and the ability to install apps from Firefox Marketplace. The problem is with Marketplace, it does not install any app, even an online app! After waiting for 1 to 2 hours, it shows that the app could not be installed. Marketplace has been allowed to install add-on but it fails to do so. I am posting also an Image file which may help you all guys to detect the problem. All the plugins are updated, Using Nightly, no point of upgrading to latest version of Firefox, Updated Windows. [64 Bit Nightly, 64 Bit Windows] Thanks in Advance.