@mention Notifications Not Being Delivered Across Azure DevOps Services

Question

I initially posted this question on the Japanese version of Microsoft Q&A, but I was informed that Azure DevOps is not supported there. Therefore, I am reposting it here. The original Japanese post can be found at the following URL:https://learn.microsoft.com/ja-jp/answers/questions/2259217/azure-devops-@?comment=question&translated=false#newest-question-comment.

Issue

In various Azure DevOps services (such as Discussions in Boards, Pull Requests in Repos, and others), when we use @mention to notify a user, the notification does not get delivered to the mentioned user. I suspect the direct cause as described below, but I have not been able to find a solution.

Suspected Direct Cause

When I log in to Azure DevOps as a user who is not receiving notification emails, and go to "User Settings" > "Profile" to check the "Contact email," it shows the Azure User Principal Name (UPN) instead of the email address where notifications are supposed to be delivered. Since the intended notification email address is different from the Azure UPN domain and address, I assume this mismatch is preventing @mention notification emails from being received.

Actions I Have Tried

I tried to change the "Contact email" mentioned above, but it is disabled and cannot be edited. I attempted the following steps without success:

• A guidance message said, "If you can't find your setting here, please visit the complete Azure DevOps Profile Page." I accessed the provided link, clicked "Edit Profile," and checked the "Contact email" there, but it was also disabled and could not be edited.
  
• On that page, another guidance message said, "Some information cannot be edited here. Click here to edit my personal information." I accessed the link, navigated to the "My Account" section via the image, but could not find the relevant setting.
  

Under "Security & Privacy," it mentioned, "To update your password or contact settings, or to view your organization’s privacy statement, go to the new My Account portal," so I accessed that portal as well.

However, I could not find any screen that allows me to edit the contact email address there either. Notably, there was an email icon displayed, and the address listed there is the intended email address where we want notifications to be sent.