DHL Shipping Error

I just went live with my website today. I noticed that around 8:00 in the evening, the system will not provide any qoutes for DHL. The error that comes up is that the day has already ended. Choose another day. Does anyone know what file I need to look at. I want to have the system get a quote for the following day. That way there should not be any more problems. I never ship out anything the same day.