Since two days ago I've stopped getting instant e-mail notifications about new posts to threads in which I'm active (subscribed).

I haven't been making any changes to my profile settings.

Any idea of what might be the cause and how to fix it?

Thank You!!!

I didn't find the right solution from the Internet.
References
http://www.tennisforum.com/53-tennisforum-com-bug-error-reporting-questions/1284603-no-more-instant-e-mail-notification.html
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