Customer reported that free/busy works for all rooms except one (all rooms reside in the same Domino NSF).
Symptoms included:
The problematic room appears correctly in Quest tools and in Exchange.
No request is logged on the CMN Free/Busy server when attempting to read this room’s free/busy (other rooms do produce logs).
Exchange-side error: “Microsoft.Exchange.InfoWorker.Common.Availability.InvalidSmtpAddressException: The email address provided is not a valid SMTP address.”
The room’s SMTP address contains an ampersand, for example: Room&123@domain.example
Although the ampersand character “&” is technically permissible in RFC-compliant SMTP local parts, some services involved in free/busy lookups (Exchange Availability, clients, or intermediary components) enforce stricter validation. As a result, requests using an address with “&” are rejected as invalid before they reach the CMN Free/Busy server, producing InvalidSmtpAddressException and no CMN logs for that room.
Add a clean SMTP alias and use it for free/busy
In Exchange, add an SMTP alias for the room that does not include special characters (letters, numbers, periods, and hyphens are safe).
Optionally set this alias as the primary SMTP if you want it to be the canonical address.
Retest using the clean alias
From Outlook/OWA Scheduling Assistant, check the room’s availability using the new alias.
Confirm that the CMN Free/Busy server now logs the request and availability is returned successfully.
Update references and allow for directory propagation
Update any documentation, booking templates, or shortcuts to reference the clean alias.
Allow time for GAL/Autodiscover/OAB updates to propagate before retesting widely.
Preventive guidance
Avoid using special characters (such as &, #, %, +, =) in SMTP addresses for mailboxes whose addresses will be used in free/busy lookups across systems.
Standardize room addresses to simple, unaccented characters to minimize cross-system validation issues.
