On September 4, 2026, SMTP2GO experienced an 11.7-hour email delivery incident where messages to Microsoft-hosted and other domains became stuck in a "Processed" state, causing delays and greylisting. The root cause was a Microsoft Exchange Online service degradation (incident EX1467029), which created excess server load on SMTP2GO's outbound queues and cascaded to affect other providers including Gmail. A fix was implemented and mail queues returned to normal by 20:41 UTC.
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This incident has been resolved and mail queues have returned to normal.
Thank you for your patience.
Excess server burden caused by knock on effects from the Microsoft service issue caused abnormal outbound queues.
A fix has been implemented and we are monitoring server queues
Our technical team is investigating an issue with some messages to various providers being shown as "Processed" and not reaching the recipient
We are investigating as this issue has now started affecting other providers, like Gmail
Microsoft has accepted responsibility for the current email delays. More details can be found on their status page and below:
Issue ID: EX1467029
Affected services: Exchange Online
Status: Service degradation
Issue type: Incident
Start time: Sep 4, 2026, 10:19 PM GMT+12
User impact
Users may experience a delay in sending and receiving email messages from external domains in Exchange Online.
More info
Users may experience intermittent “Server busy” errors, affecting multiple mailboxes.
Scope of impact
This issue impacts users who may be attempting to send and receive email messages from external domains in Exchange Online. This information may be updated as our investigation continues.
While we continue to handle the ongoing issue with Microsoft domains, all indicators point to a larger, global issue with Microsoft itself. We will continue providing updates as they are available.
https://groups.io/email-provider-status?isp=Microsoft+365
Our team is currently investigating an issue causing some emails to remain in the “Processed” state to Microsoft email addresses, resulting in delivery delays and greylisting. We are working to resolve the issue.
We recommend safelisting wherever possible: https://support.smtp2go.com/hc/en-gb/articles/360000471954-Allowlisting-IP-Addresses-With-Microsoft-365
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