A recent technical problem has impacted the reliable delivery of one-time passcodes (OTP) for some users of Exchange Online. Reports indicate that a DNS issue is the underlying cause of this service disruption.
The issue appears to stem from failures in resolving domain names for certain external services. This prevents email delivery containing the crucial OTP codes, which are often required for secure logins or transactions. While not affecting all users universally, those attempting to receive these specific types of emails from external sources may experience significant delays or complete non-delivery of the passcodes.
Microsoft is aware of the situation and is actively investigating to identify the root cause and implement a fix. The focus is on restoring normal email flow and ensuring that all users can reliably receive security passcodes necessary for accessing various services. Updates are being provided as their investigation progresses towards a resolution for the impacted Exchange Online service.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-links-dns-issue-to-exchange-online-otp-delivery-failures/
