Wcf service not able to return huge data

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WCF

hello,
I am using wcf service to return collactio of data in my MVC application.
My service is working fine if the count of data is < 100. if it incerease more than 100 then it is showing Error:500 and it is not returning to the controller.

In my WCF:
public List<string> GetName(id,dep)
{
List<string> name= new List<string>();
urlList = Obj.GetNameList(id, dep);
return urlList;
}
In my Controller:

this.ViewData["name"] = service.GetName(id, dep);

If urlList.count > 100 its giving ErrorCode:500 , The connection is getting closed while returing the data from service to controller.

Any suggestion Plz Help!