If it's time dependent, then it's very probable that the problem is NOT on your side but on the server's side. It may be overloaded before midnight.
You may also gave a router or proxi set to refuse or restrict access to game sites during some periods. Also not dependent on your computer.
The procedure to enable access, if available to you, depends entirely on what is enforcing the access monitoring and limitation.
If you pass by your work place, or a school, network, then you MUST NOT attempt to bypass that limiting in ANY way.
It can lead to your been fired.
In school, you can loose ALL internet access, get into detention or getting expelled.
Electro, August 2011