Other users did not receive email notification when I tagged them in comments

[Afiqah]

I try to tag other users in comment section however they did not receive any email notifications. However when I ask my colleague to tag other users in the same ticket, the other users receive it. Do you have any idea why this is happening?

[caglad]

The user may have those notifications turned off - they need to go into their personal settings (top right) and check to make sure "mentions" send them a notifications