Possible resolution I've discovered. If you have a machine that was provided by an OEM (HP, Dell, etc.), it's possible that they've put your network connection into the "Public" domain (Network Profile) rather than "Private". If you click on your WiFi icon in the system tray, find your active connection and click properties, the screen that appears will allow you to change it from Public to Private. Once I did this, I was able to get past this without having to disable Windows Defender Firewall or the Real-time Protection antivirus setting.
If anyone could try this and let me know if it resolves your issue, it would be appreciated. Of course I'm not 100% certain that this one setting is what fixed my issue or not, but if this does resolve it, others will be able to benefit and Microsoft can add it to their list of recommendations for their Store troubleshooting page.
Thanks!