Thread subscriptions notifications not working

[clubpromos]

Hi,

Sorry if this has been already discussed, I couldn't find any clear answer that addresses the issue:
1. Users receive email notifications just fine for PM.
2. BUT none of them get notifications for threads they subscribed to any longer. I have no idea what has changed. It's been like this for weeks and for the life of me I can't find out why...(((

Can someone help out with this?

Thanks