Azure AD B2C Emails not being delivered

Check the tenant-specific Azure Service Health dashboard first; a sudden tenant-wide failure across multiple email providers, while B2C records successful send operations, should be treated as a possible service-side delivery issue rather than repeating recipient-address tests.

1. Check tenant-specific service health

1. Sign in to the Azure portal using an account with access to the relevant tenant or subscription.
2. Search for Service Health.
3. Open:
   • Service issues for active incidents.
   • Health advisories for degraded functionality.
   • Health history for an event that began this morning.
4. Filter by tenant/subscription scope and look for Azure Active Directory B2C, identity, authentication, or email/OTP delivery impact.
5. Open any matching notification and record its tracking ID, affected region, start time, and recommended action.

Service Health is personalized to your environment, whereas the public Azure Status page primarily provides a global view of widespread incidents.^1^ Service Health also distinguishes tenant-level from subscription-level events.^2^

If an incident is listed, monitor that incident rather than changing the B2C policy. The public B2C status page can be checked as a secondary signal, but a clean public page does not exclude tenant- or region-scoped impact.^3^

2. Preserve evidence from a controlled reproduction

Since multiple providers have already failed, run only one or two controlled attempts and capture:

• Exact timestamp in UTC.
• B2C tenant ID or domain.
• Policy/user-flow ID.
• Application ID.
• Recipient domain, with the full address redacted.
• Region and client IP, if relevant.
• Audit event result and correlation ID.
• Screenshot of the verification page after Send code.
• Whether Resend code was used.

In Azure portal → Azure AD B2C → Activities → Audit logs, filter to the test time and open the matching activity. Download the results as CSV before they expire; B2C portal audit events are retained for seven days.^4^

A successful B2C audit entry establishes that the B2C operation completed successfully, but it does not provide recipient-mail-system delivery traces. Avoid repeatedly requesting new codes during delayed delivery, because users can receive several codes later and attempt the wrong one.

3. Enable longer-term diagnostics if not already configured

For future events:

1. Switch to the Azure AD B2C tenant.
2. Open Microsoft Entra ID → Monitoring → Diagnostic settings.
3. Select Add diagnostic setting.
4. Select AuditLogs and SignInLogs.
5. Select Send to Log Analytics Workspace, choose the workspace, and save.

Only AuditLogs and SignInLogs are supported diagnostic categories for B2C tenants. Configuring the cross-tenant Log Analytics destination requires the documented Azure Lighthouse setup, including the stated B2C Global Administrator and subscription Owner prerequisites.^5^

Do not expect these logs to provide SMTP message traces or a recipient-server rejection reason.

4. If this is a custom policy

Use Application Insights to trace the affected user journey:

1. Capture the B2C correlation ID from the sign-in page source.
2. Find that correlation ID and timestamp in Application Insights.
3. Inspect the invoked technical profiles, exceptions, claims transformations, and whether the email-verification technical profile completed.

Application Insights is the documented troubleshooting path for custom-policy execution and normally has a short ingestion delay.^6^

This step applies to custom policies; it is not a substitute for Microsoft-side mail-delivery telemetry when the built-in B2C sender reports success.

5. Escalate if Service Health shows nothing

Open a B2C support request:

1. Switch to the Microsoft Entra tenant associated with the Azure subscription; support cases cannot currently be submitted directly from the B2C tenant.
2. Go to Microsoft Entra ID → Troubleshooting + Support → New support request.
3. Select:
   • Issue type: Technical
   • Service type: Azure Active Directory Business to Consumer (B2C)
4. Include the UTC timestamps, tenant and policy IDs, correlation IDs, audit exports, affected regions, recipient domains, and confirmation that independent providers were tested.
5. Enable Advanced diagnostic information when organizational policy permits it.

Microsoft documents this as the escalation route for unresolved B2C problems.^7^

References

1. Azure Service Health
2. Azure Service Health portal
3. Azure status
4. Accessing Azure AD B2C audit logs
5. Monitor Azure AD B2C with Azure Monitor
6. Troubleshoot Azure AD B2C custom policies and user flows (b2c-custom-policy)
7. Find help and open a support ticket for Azure Active Directory B2C