Krystal incident
Issues with outbound mail sending to Microsoft services email addresses
Krystal experienced a minor incident on February 26, 2026 affecting Sirportly, lasting —. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- identified Feb 25, 2026, 10:34 AM UTC
Status: Identified We're aware of an issue with a number of outbound emails sent via Sirportly, to Microsoft services email addresses, i.e. outlook.com, live.com and hotmail.com/co.uk . The errors provided by their mail servers suggest a rate-limiting issue but as this is a false-positive due to no detected increase in mail rates, or any unexpected / unsolicited mail being sent from any customers, we've requested removal directly using their SNDS system. We'll provide further updates as soon as we have them. Affected components Sirportly (Degraded performance)
- identified Feb 25, 2026, 03:02 PM UTC
Status: Identified We are continuing to see both new, and retried mail messages rejected by Microsoft, with no sign yet of successful deliveries. This is still limited to Microsoft email services only, and other mail services are all delivering successfully. Affected components Sirportly (Degraded performance)
- resolved Feb 26, 2026, 10:16 AM UTC
Status: Resolved We're seeing emails to Microsoft services returning to normal overnight and this morning, with no further rate-limit related errors. The majority of emails in this state should retry but customers can reach out via [email protected] if they require any specific messages to be checked. At the same time, we've seen a number of posts online relating to the same rate-limit issue - suggesting a more broad problem at Microsoft's end affecting multiple sending services. Affected components Sirportly (Operational)