Why do I get 404 when I receive email There is a new comment on the question that you follow?

I’m following certain topics here in this forum. And when I receive email that someone has made a comment to it I can’t open it using the link in the email nor can I open it from the top notifications either. see pics related. Is this a bug or something I can fix myself? 
1 answers

Hi Jouni Miikki,

I have faced the  issue many times . It might be The comment must have been deleted or might be bug( sure).