Hotspot Problem (Login Client)

Hello!
My problem is as follows:
It is only recently that I am presenting a problem with some customers when trying to access your account hotspot (user manager), which is that when you open the website to try to login never shows the login page, and try putting the address of the server and still not load, is the only solution to restart the server Mikrotik.

We are using the version 3.20 RouterOs with Level 5, I have also released the cache with a maximum of 2mb and besides blocking large audience (approx 700 sites advertising)

I suguieren?
Thanks!