No notifications for other people

From some time, other people are not receiving notifications from my personal messenger. When i send them a message, they would end up saying that they didn't recieve the notification for it.

This is really frustrating. I hope someone could help, please. I use my messenger normally.

I'm not sure if this is related or not, but issues with notifications seems to extend to at least May, and I haven't heard of any solutions yet:

http://forums.rpgmakerweb.com/index.php?/topic/27075-follow-notifications/