Portal redirection is not working

Portal redirection does not work, SSID are displayed but portal page does not appear.

After configuring portal authentication and the free rules template, the users were able to see the SSID and connect to it but the portal page redirection was not working. 

We were able to open the portal page when we input its IP address, but cannot access it when used the URL to access the portal page.

we checked the configuration for the free rule template;

But we did not find the DNS server ip configured to do the resolution of ip to URL, so we permit the DNS IP address on free-rule-template, then portal page redirect normally.

[campus_ACU2_1]free-rule-template  name default_free_rule

[campus_ACU2_1-free-rule-default_free_rule]free-rule 1 destination ip x.x.x.x

Missing configuration.

Add the DNS server ip to the free rule template.