We are no longer seeing delays in Office 365 incomings in the US region, we keep monitoring the issue.
Posted 21 days ago. Sep 04, 2018 - 16:55 UTC
Microsoft seems to have issues with a datacenter, explaining the delays we are experiencing. Not all customers are impacted. Microsoft offers more information on their status page: https://status.office365.com/ and through your Office Admin Portal.
Posted 21 days ago. Sep 04, 2018 - 13:43 UTC
We are currently investigating delays in Office 365 incomings in the US region. We are checking with Microsoft directly.