Name of a horror movie from the 90s

Hello everyone. Twenty (or more) Years ago, I watched a horror movie from the 90s. I don't remember the story or the name of the movie, but i remember this: The people of a small town in USA fall into sleep and they had the same dream: a voice that said: "this is not a dream, this is a message from 1999". And as I can remember, it was something about mirorrs.

Has anyone an idea, what the name of the movie is?

Thanks a lot!