[Monitoring] Email delivery issues

We are experiencing problems with incoming email from Outlook/Hotmail, and outgoing email to services connected via ATT in the US.

We’re currently investigating these delivery issues and expect them to be resolved soon.

We apologize for any inconvenience caused.

Update 2024-06-10 12:00 CEST (6 AM EDT, 3 AM PDT)

The problem with incoming email from Outlook/Hotmail appears related to a routine maintenance update made before the weekend to keep DANE (DNS-based Authentication of Named Entities) working properly.

DANE is a standard that was implemented in order to secure email communications between mail servers. Changes made to the TLSA (Transport Layer Security Authentication) records utilized by DANE appear to be incorrectly rejected by Microsoft’s email servers, causing email validation problems for Exchange Online users.

After reverting these changes, email from Outlook/Hotmail is being correctly delivered to Runbox again.