Content Filter not working USG Flex 500 issue

Hi,

When i enable Content Filter and(or) DNS Content Filter in Policy Control, http and https connection become very slow. I think that because Content Filter not resolving url(domain name).

in cli:

Router(URL)# https://community.zyxel.com
% ret err = -4
result: Error
The query takes: 1.000000 seconds

in web:

Help me solve the problem, thanks.