The codes 0x80073cf0 and 0x803F8001 are errors with the Microsoft Store. It could be caused by the store cache, incomplete downloaded apps, Windows Update failure, and similar concerns.
Since these error codes are an issue with the store itself, they can affect a variety of apps and not a specific app. These glitches occur only on Windows versions: 8, 8.1, and 10. 
The symptom could begin with the slowing down of the operating system and will affect the access to the Microsoft Store. Even if there is access to the Microsoft Store, it will not allow downloading any app even if you restart your device.
The Microsoft Store Error Codes 0x80073cf0 and 0x803F8001 can be fixed manually and there are several ways to do it:
Restarting Windows Updates
  1. Press Win key.
  2. Type cmd.
  3. Right-click on the search results.
  4. Select Run as Administrator.
  5. Type net stop wuauserv when the elevated Command Prompt window opens.
  6. Press Enter.
  7. Wait for the command to be executed.
    Note: Don’t close the window.
  8. Type rename c:\windows\SoftwareDistribution softwaredistribution.old command.
  9. Press Enter.
  10. Type net start wuauserv.
  11. Press Enter.

    After these steps, close Command Prompt window and reboot your PC.
Using Services Tool
  1.  Press Win key + R.
  2. Type services.msc.
  3. Press Enter.
  4. Right-click Windows Update.
  5. Select Stop.
  6. Open Windows folder on the disk partition where Windows OS is installed.
  7. Open SoftwareDistribution folder and delete all files that are stored.
  8. Open services.msc again by following steps 1 to 3.
  9. Right-click Windows Update.
  10. Select Start.

    After these steps, reboot the PC and try to login to Microsoft Store.
Removing Cache
  1. Press Win key + R.
  2. Type WSReset.exe
  3. Press Enter.

    Note: When you will be shown a Command Prompt and Microsoft Store windows, it means that Microsoft Store cache has been successfully cleaned. Then reboot your PC.
Running Registry Repair
  1. Open Start.
  2. Type Advanced Startup Options.
  3. Click on the results.
  4. Select Restart now to boot your PC in an Advanced startup mode.
  5. Choose Advanced Options.
  6. Press Troubleshoot.
  7. Select Automatic Repair and wait for the system to restart.