Hi You might try a reset! Would help to know what device you're having this issue on as abhishek has suggested! This has helped some users!
: Run wsreset and, if needed, reboot. The easiest way to do so is to open Cortana or the Run dialog (WINKEY + R) and type wsreset followed by Enter. The Windows Store app will then open. I didn’t need to reboot, either: Upon checking Downloads, and retrying the app, it started immediately downloading.