Sometimes I don't receive notifications

In the past couple of weeks I've noticed that sometimes (quite often, actually) I don't receive notifications for messages. I have to manually check my inbox to see whether someone has written to me. At first I thought that I had accidentally marked the notifications as read or that I had missed them, but as there were more and more cases, I started checking my notification history on MyDramaList and I discovered that the notifications were also not there, so now I'm sure that MyDramaList simply didn't send them to me. Are other people experiencing this? Is there an issue with the server?

 Ji-N:

Are you referring to email, app notification, or website notifications?

I'm referring to website notifications. But when I don't receive notifications on the website, I also don't get e-mail notifications.

Update (June 16): I still have this problem.

Update (September 7): It's only happened once in the past month, so it seems better now.