Notice history

No notices reported this month

Resolved
September 04, 2026 at 1:20 PMUTC
Resolved
September 04, 2026 at 1:20 PMUTC
This incident has been resolved by Microsoft. We're working on emptying the queues and we expect all email to be delivered soon.
Monitoring
September 04, 2026 at 12:00 PMUTC
Monitoring
September 04, 2026 at 12:00 PMUTC
Since 9:50 CEST this morning Microsoft has had issues receiving email. This means that many emails sent to Office365 recipients will result in a soft bounce with this message:
52.101.68.10 failed after I sent the message./Remote host said: 451 4.7.500 Server busy. Please try again later from [REDACTED]. (S77714) [DB1PEPF000509E3.eurprd03.prod.outlook.com 2026-09-04T08:16:36.825Z 08DF04AEA47F75BA]/
If you have access to the Office365 admin page they have created an issue to follow here:
https://admin.cloud.microsoft/?source=applauncher#/servicehealth/:/alerts/EX1467029
We're monitoring the issue but for now there is nothing we can do to force emails through. Emails sent during Microsoft downtime will be tried again for the following 48 hours until delivery is possible.
(We're mainly creating this issue to have a place to point clients to for updates. There is nothing we can do inhouse to solve the issue.)

Completed
September 01, 2026 at 9:11 AMUTC
Completed
September 01, 2026 at 9:11 AMUTC
Maintenance has completed successfully.
In progress
September 01, 2026 at 8:45 AMUTC
In progress
September 01, 2026 at 8:45 AMUTC
Maintenance is now in progress
Update
August 31, 2026 at 12:23 PMUTC
Update
August 31, 2026 at 12:23 PMUTC
We will be running the maintenance between 10:45 am and 11:15 am tomorrow.
Planned
August 28, 2026 at 1:15 PMUTC
Planned
August 28, 2026 at 1:15 PMUTC
We are planning for a scheduled maintenance on the 1st of September during working hours. The specific time will be added to this case when we have it.
During the maintenance you might experience delays in connecting to our SMTP and API service but the delay should be no longer than a few seconds.

Resolved
August 10, 2026 at 2:55 PMUTC
Resolved
August 10, 2026 at 2:55 PMUTC
Due to an issue with our hosting provider Heysender could not send email for a few hours this afternoon. The issue has been solved and we're monitoring the state of the service for the rest of the day.
Investigating
August 10, 2026 at 10:13 AMUTC
Investigating
August 10, 2026 at 10:13 AMUTC
We're currently experiencing issues sending e-mails from our system. We're investigating the cause.

heysender - Notice history