When someone gets mentioned under a workitem in devops the notification doesn't get send

Question

Hi!

When someone gets mentioned under a work item in devops the notification doesn't get send. When a colleague mentions me (@user) I get a mail. But for certain colleagues of me the notification mails appear to not been send.

I've tried the sollutions provided by microsoft:

The email server is down, unreachable, or rejected authenticated. The email was delivered to an unchecked folder The subscription is disabled or opted-out The event doesn't match the specified subscription filter conditions The subscription is defined to not send emails to the initiator of an event The organization level do not deliver setting is impacting email delivery The team or group level do not deliver setting is impacting email delivery You're not a member of the group or team receiving the email You're a member of an Azure Directory (AD) group and the subscription contains a @Me clause You don't have permission to view the event details, which are included in the email

But nothing seems to help. Can someone help me find the right solution? Thanks!