Windows 11 Update Failures and Installation Errors

Hi danicucci, if Exchange still says CnameMissing after several days, I would verify the records from outside your DNS provider using a public lookup tool. Make sure selector1 and selector2 are exact CNAME records, not TXT records, and that they point to the exact Microsoft 365 DKIM targets for your tenant. Also check for extra dots, spaces, old records, or DNS proxying from services like Cloudflare. If external DNS shows the correct CNAMEs and Microsoft 365 still refuses to detect them after 72 hours, open an Exchange Online support ticket and include screenshots plus external DNS lookup results.