Increased Microsoft Inbox Provider Blocks

Starting around 3:00 am PST on January 14, our engineers began investigating an issue with emails sent to Microsoft Outlook Consumer domains. Some customers may experience an increase in email block rates to Microsoft Outlook Consumer domains which include Hotmail and Outlook domains. Our Engineers are working with Microsoft. We will provide another update in two hours or as soon as more information becomes available.

Our engineering team is actively investigating this issue and we will provide more updates as soon as they become available.

Our engineering team is still actively investigating this issue and we will provide more updates as soon as they become available.

Our engineering team is still actively investigating this issue and we will provide more updates as soon as they become available.

Our engineering team is still actively investigating this issue and we will provide more updates as soon as they become available.

Our engineering team is still actively investigating this issue and we will provide more updates as soon as they become available.

Our engineering team is still actively investigating this issue, and we will provide more updates as soon as they become available.

Our engineering team is still actively investigating this issue, and we will provide more updates as soon as they become available.

Our engineers continue to work with Microsoft and will provide additional details and guidance shortly.

We have acknowledgment from Microsoft about the change in delivery behavior on their consumer email platform. Microsoft has acknowledged that the behavior is not isolated to SendGrid's environment and is not specific to our sending configuration.

Our engineering team is seeing improvement (reduction) of deferrals since the start of the incident on 1/14. Blocks have also reduced but are still at elevated levels; we will keep monitoring the behavior.

Customers that feel they are continuing to observe excessive deferrals and/or blocks should fill out the OLC Support request form at https://olcsupport.office.com/

Our Engineering team has completed monitoring and confirmed that no SendGrid-specific issues remain at this time. Microsoft has acknowledged that some senders may continue to experience elevated throttling, and has confirmed that this behavior is not isolated to SendGrid nor specific to our sending configuration.

Microsoft has advised that any additional updates will be communicated via their Smart Network Data Service (SNDS) page. Customers who continue to experience deferrals or blocks when sending to Microsoft Outlook Consumer domains (for example, hotmail.com or outlook.com) are encouraged to open a support request directly with Microsoft for further assistance:

https://olcsupport.office.com/

All SendGrid services are operating normally, and we will continue to monitor for any relevant upstream updates.