Sometimes i too face the same issue. Haven't reached to the solution yet. I will surely search for this and will share it. If you use a asus router then you may check this asus router login guide. It might be helpful to you.
@nrabus , Thanks for posting this topic. I am facing similar issue and was looking what to do next. Thanks for your solutions but can anyone provide a permanent solution to these.Your answers helped me but i am still facing the issue .Thank you in advance.