Sending, receiving, and organizing email in Outlook.com
That sender address is actually a legitimate Microsoft domain. Emails from @ms.microsoft.com are used by Microsoft for certain automated alerts, including Office 365 notifications.
However, a real-looking sender address alone does not guarantee the email is safe. Phishing emails can spoof or mimic legitimate addresses, or use compromised systems to send malicious messages.
What matters more is the content and behavior of the email. Check whether it is asking you to click links, reset your password, verify your account, or download attachments. Look closely at any links by hovering over them and seeing if they truly point to a Microsoft domain such as microsoft.com, office.com, or live.com. Be cautious if the message creates urgency, contains unexpected attachments, or has unusual wording.
Also consider whether the email makes sense in context. For example, if it claims there was a login attempt or security alert, you can verify that independently by signing into your Microsoft account directly through the official website rather than clicking anything in the email.
If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.
hth
Marcin