Email Delivery Delays
Last updatepostmortemSep 7 · 08:29 UTC
What happened?
On September 4th 2026, some Signhost email notifications, including signing invitations and status updates, were delivered later than usual. During this period, the Signhost platform remained fully operational. Document signing, transaction processing and API functionality were not affected.
What caused the issue?
Our investigation confirmed that the delays were caused by a broader Microsoft 365 Exchange Online incident affecting email processing and delivery. Microsoft reported delays and “server busy“ errors affecting Exchange Online infrastructure. The issue originated outside of Signhost and was not related to the Signhost application, infrastructure or services.
It is important to note that Signhost does not use Microsoft Exchange Online to send email notifications. Our email delivery is handled through SparkPost, our email service provider.
More information about the Microsoft incident can be found here: Exchange Online outage causes email delays and server busy errors
What we did?
We worked closely with our email service provider to monitor the situation and verify the root cause. Throughout the incident, we continuously monitored Signhost services and confirmed that core platform functionality remained unaffected.
Once Microsoft resolved the Exchange Online incident, email delivery returned to normal. We have verified that email notifications are now being delivered as expected, with no further delays observed.
We would like to reassure customers that no documents, transactions or customer data were impacted and no action is required on your part.
Reported by Signhost Verified Signing on their status page.