Microsoft Mail Delivery Delays and Temporary Rejections
Monitoring - We are currently seeing elevated temporary rejection rates for email delivered to Outlook.com, Hotmail, and other Microsoft-hosted addresses. Microsoft has acknowledged the issue and is actively investigating. This is a industry-wide issue and not isolated to any specific account. We will continue to monitor and update this page as we receive more information.

Next update: When Microsoft posts a resolution or Bird observes delivery rates normalizing
Feb 26, 2026 - 12:55 EST
Uptime over the past 90 days. View historical uptime.
SparkPost Application (WebUI) Operational
90 days ago
100.0 % uptime
Today
SparkPost Application - USA Operational
90 days ago
100.0 % uptime
Today
SparkPost Application - EUROPE Operational
90 days ago
100.0 % uptime
Today
SMTP Delivery (Outbound Message Delivery) Operational
90 days ago
100.0 % uptime
Today
SMTP Delivery - USA Operational
90 days ago
100.0 % uptime
Today
SMTP Delivery - EUROPE Operational
90 days ago
100.0 % uptime
Today
Transmissions API Operational
90 days ago
99.99 % uptime
Today
Transmissions API - USA Operational
90 days ago
99.99 % uptime
Today
Transmissions API - EUROPE Operational
90 days ago
100.0 % uptime
Today
SMTP API Operational
90 days ago
100.0 % uptime
Today
SMTP API - USA Operational
90 days ago
100.0 % uptime
Today
SMTP API - EUROPE Operational
90 days ago
100.0 % uptime
Today
Metrics API Operational
90 days ago
100.0 % uptime
Today
Metrics API - USA Operational
90 days ago
100.0 % uptime
Today
Metrics API - EUROPE Operational
90 days ago
100.0 % uptime
Today
Events API Operational
90 days ago
100.0 % uptime
Today
Events API - USA Operational
90 days ago
100.0 % uptime
Today
Events API - EUROPE Operational
90 days ago
100.0 % uptime
Today
Relay Webhooks Delivery Service Operational
90 days ago
100.0 % uptime
Today
Relay Webhooks - USA Operational
90 days ago
100.0 % uptime
Today
Relay Webhooks - EUROPE Operational
90 days ago
100.0 % uptime
Today
Sending Domains API Operational
90 days ago
100.0 % uptime
Today
Sending Domains API - USA Operational
90 days ago
100.0 % uptime
Today
Sending Domains API - EUROPE Operational
90 days ago
100.0 % uptime
Today
Suppression List API Operational
90 days ago
100.0 % uptime
Today
Suppression List API - USA Operational
90 days ago
100.0 % uptime
Today
Suppression List API - EUROPE Operational
90 days ago
100.0 % uptime
Today
Event Webhook Delivery Service Operational
90 days ago
100.0 % uptime
Today
Event Webhooks - USA Operational
90 days ago
100.0 % uptime
Today
Event Webhooks - EUROPE Operational
90 days ago
100.0 % uptime
Today
Engagement Tracking Service Operational
90 days ago
100.0 % uptime
Today
Engagement Tracking Service (redirecting clicks and serving opens) - USA Operational
90 days ago
100.0 % uptime
Today
Engagement Tracking Service (redirecting clicks and serving opens) - EUROPE Operational
90 days ago
100.0 % uptime
Today
Mailbox Provider Service Interruption Degraded Performance
Blocklist API Operational
90 days ago
100.0 % uptime
Today
Blocklist API - USA Operational
90 days ago
100.0 % uptime
Today
Blocklist API - EUROPE Operational
90 days ago
100.0 % uptime
Today
Alerts API Operational
90 days ago
100.0 % uptime
Today
Alerts API - USA Operational
90 days ago
100.0 % uptime
Today
Alerts API - EUROPE Operational
90 days ago
100.0 % uptime
Today
Operational
Degraded Performance
Partial Outage
Major Outage
Maintenance
Major outage
Partial outage
No downtime recorded on this day.
No data exists for this day.
had a major outage.
had a partial outage.

No incidents or maintenance related to this downtime.

Feb 26, 2026

Unresolved incident: Microsoft Mail Delivery Delays and Temporary Rejections.

Feb 25, 2026

No incidents reported.

Feb 24, 2026
Elevated 5xx Transmissions API error rates and latency for some SparkPost customers (US hosted only)
Resolved - This incident has been resolved.
Feb 24, 14:41 EST
Monitoring - A fix has been implemented and we are monitoring the results.
Feb 24, 14:38 EST
Identified - The team has identified the root cause. There is a core networking issue that has impacted sending across the clusters.
Feb 24, 14:34 EST
Update - We are continuing to investigate this issue. We still see 5xx errors on mail injections and degradation.
Feb 24, 14:25 EST
Update - We are continuing to investigate this issue.
Feb 24, 14:07 EST
Investigating - We are experiencing an elevated level of errors and latency on the Transmissions API (injection API) for some SparkPost customers. Please retry any 5xx error.

Note: This issue does not impact SparkPost customers hosted in the EU.
Feb 24, 14:07 EST
Outbound message delivery is delayed/slow for some SparkPost customers (US hosted only)
Resolved - This incident has been resolved.
Feb 24, 13:17 EST
Monitoring - A fix has been implemented and we are monitoring the results.
Feb 24, 12:34 EST
Identified - The issue has been identified and a fix is being implemented.
Feb 24, 12:19 EST
Investigating - We are currently investigating this issue. No messages are lost.
Feb 24, 10:01 EST
Feb 23, 2026

No incidents reported.

Feb 22, 2026

No incidents reported.

Feb 21, 2026

No incidents reported.

Feb 20, 2026
Outbound message delivery is delayed/slow for some SparkPost customers (US hosted only)
Resolved - This incident has been resolved.
Feb 20, 11:33 EST
Update - We are continuing to monitor for any further issues.
Feb 20, 11:15 EST
Monitoring - A fix has been implemented and we are monitoring the results.
Feb 20, 11:14 EST
Investigating - We are currently investigating this issue.
Feb 20, 11:06 EST
Feb 19, 2026

No incidents reported.

Feb 18, 2026
Outbound message delivery is delayed/slow for some SparkPost customers (US hosted only)
Resolved - This incident has been resolved.
Feb 18, 12:06 EST
Update - We have seen recovery. We will continue monitoring for the next 60 minutes to ensure message queues stay stable.
Feb 18, 11:15 EST
Monitoring - We continue to see strong recovery of the mail queues and message delivery. We expect all remaining delayed messages to be delivered in the next 5 minutes.
Feb 18, 10:59 EST
Update - We have begun to see improvements to outbound mail delivery delays. We anticipate full recovery in the next 30 minutes.
Feb 18, 10:15 EST
Identified - The issue has been identified and a fix is being implemented.
Feb 18, 10:02 EST
Investigating - We are investigating an increase in delivery latency for some outbound messages. (NOTE: This does not impact our customers hosted in the EU.)
Feb 18, 09:51 EST
Feb 17, 2026

No incidents reported.

Feb 16, 2026

No incidents reported.

Feb 15, 2026

No incidents reported.

Feb 14, 2026

No incidents reported.

Feb 13, 2026

No incidents reported.

Feb 12, 2026

No incidents reported.

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