Exchange & Mail Flow
Exchange Online and on-premises mail flow failures, mailbox database recovery, federation trust breaks, hybrid mail routing, and outbound delivery disruptions.
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Exchange Online mail flow problemsMail not delivering, NDRs, mass quarantine, or hybrid connector failure. The diagnosis runs from envelope sender to mailbox, in order.
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Exchange 2013 mailbox database evacuation after eseutil offline repairAfter eseutil.exe offline repair is performed on an Exchange 2013 mailbox database, Exchange emits hourly warnings that Exchange-level logical consistency can no longer be guaranteed and requires the…
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Exchange On-Premises Federation Trust Broken with SOAP Auth Failure After Office 365 Domain VerificationAfter deleting and recreating an on-premises Exchange federation trust during Office 365 domain verification, Test-FederationTrust fails with SOAP fault errors 0x80048821 / 0x80041012 ('passwords do…
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Exchange Online Mail Flow Disruption: onmicrosoft.com Outbound and Direct Send ChangesMicrosoft's upcoming Exchange Online service changes will impact tenants sending outbound mail via the default onmicrosoft.com domain and those relying on Direct Send for inbound routing. The Change…
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Exchange 2007 TLS Certificate UntrustedRoot Failure for Domain-Secured SMTP DeliveryExchange 2007 fails to deliver mail to domain-secured recipient domains when the remote SMTP server presents a TLS certificate issued by a private or unknown certificate authority, resulting in an 'U…
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Exchange ActiveSync Certificate-Based Authentication Retirement — Mobile Email MigrationMicrosoft is retiring direct certificate-based authentication (CBA) for Exchange ActiveSync (EAS) in Exchange Online by end of 2026, announced May 8, 2026. Organizations relying on CBA for mobile ema…
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Microsoft 365 SMTP Relay Configuration — Enabling IP-Based SMTP Sending for On-Premises Devices via Exchange Online ConnectorOn-premises devices (printers, scanners, applications) fail to relay outbound email through Exchange Online when no inbound connector exists to authenticate by IP address. Without proper configuratio…