Need some help about Duping!

Hello! I wanna know if duping requires an server at certain moment like, example: I always dupe on USSouth at 4pm , but at 7pm i can't dupe at it anymore! I would like to know if anyone dupes at servers only at certain moments. Please, just let me know

The time of the day has nothing to do with duping, although it is a bit better to get a server with a bit more people, it'll cause a bit more server lag during the "connecting"/"connected".