Mail Latency Report

Message delivery times across your mail flow. Identifies delays in connectors, transport rules, or external delivery to help troubleshoot mail delivery issues.

Overview

The Mail Latency Report measures how long messages take to be delivered from sender to recipient across your Exchange Online environment. This report helps identify bottlenecks in mail flow, whether caused by transport rules, connectors, third-party services, or external mail servers.

Report Columns

Latency Breakdown

The report analyzes latency across different stages:

• Internal Delivery — Messages between users within the same tenant
• External Inbound — Messages arriving from external senders
• External Outbound — Messages sent to external recipients
• Connector Latency — Delay introduced by mail flow connectors
• Transport Rule Processing — Time spent evaluating transport rules

Latency Thresholds

Filters

• Date Range — Last 7 days, 30 days, 90 days, or custom
• Direction — Internal, External Inbound, External Outbound
• Connector — Filter by specific mail flow connector
• Domain — Filter by sender or recipient domain
• Tenant — Filter by managed tenant

Troubleshooting

When latency is higher than expected, check:

1. Mail flow connectors for misconfigurations or partner server issues
2. Transport rules with complex conditions that slow processing
3. Third-party mail filtering services adding delay
4. DNS resolution issues for external domains
5. Microsoft service health for Exchange Online incidents

API Reference

• GET /api/reports/exchange/mail-latency — Get mail latency statistics
• GET /api/reports/exchange/mail-latency/breakdown — Get latency by stage
• POST /api/reports/exchange/mail-latency/export — Export report data