Sam reported Office 365 non-delivery errors for website intake lead notifications addressed to six demandsam.com recipients. The current failure was a Microsoft 365 recipient-resolution issue, not a full demandsam.com domain outage. The bad addresses were alyssia@demandsam.com, haney@demandsam.com, chymez@demandsam.com, kyle@demandsam.com, janelle@demandsam.com, and angelica@demandsam.com.
Outlook NDR review showed repeated bounces for New Website Intake Lead messages, including Lead #66 on 2026-05-12 at 15:41 UTC. Microsoft returned 550 5.1.10 RESOLVER.ADR.RecipientNotFound for the six addresses. The same original message also included valid recipients, including timmera@demandsam.com and janette@demandsam.com, so the accepted domain was working but six aliases or mailboxes were missing.
Graph and Exchange checks confirmed demandsam.com is verified in the tenant. The six intended people have enabled kylawoffice.com mailboxes, but the matching demandsam.com aliases do not exist on those users. Direct alias writes through Graph and Exchange were blocked because synced mailbox proxyAddresses are read-only in cloud management and must normally be changed on the synced source object.
A reversible tenant-side delivery fix was applied in Exchange Online. Hidden distribution groups were created at the six failing addresses, each with one intended mailbox member:
The groups are hidden from address lists and allow external senders, which matches the lead-notification use case.
Exchange verification returned Ready for all six addresses. Each address resolves as a MailUniversalDistributionGroup, each group has exactly one member, hidden-from-address-lists is true, sender authentication required is false, and member verification is true.
Local backup and proof artifact: /Users/samaguiar/Documents/Codex/_backups/exchange-intake-demandsam-groups-created-2026-05-12.json
A pre-change alias backup was also saved before the direct-alias path was attempted: /Users/samaguiar/Documents/Codex/_backups/m365-intake-aliases-before-2026-05-12.json
The stale list still needs source cleanup. Cloudways and WordPress checks did not find the current lead generator in reachable WordPress storage. Gravity Forms entries stopped on 2026-04-09. The custom wp_sal_contact_leads table stopped at lead 46 on 2026-04-28, while the bounces were leads 61 through 66 from 2026-05-08 through 2026-05-12. Exact searches for demandsam.com did not locate the bad list in the reachable WordPress database, active must-use plugin code, or PHP files under the Cloudways applications. That points to a downstream automation, a moved/hidden runtime source, or a Microsoft/Litify process formatting the same old lead email template.