Newegg has been subjected to a grilling on Reddit in recent days. One such thread reports that a Microsoft rep has stated that two Windows 10 OEM keys sold by the online retailer were pirated. Newegg has since promised to send out physical replacements for those who have bought keys that will not activate.
https://www.notebookcheck.net/Microsoft-accuses-Newegg-of-selling-pirated-Windows-10-keys.366076.0.html