We're having issues with a Hotspot Portal as it is not redirecting.

Our current setup is a
 

ISP modem - TPLink POE Switch - EAP615-Wall
we're using the omada cloud controller.

We configured everything as per manual, SSID, LAN, WLAN, Hotspot Portal, Voucher etc. we are currently testing the connecting to the hotspot but we're not being redirected to the Portal as it is not loading. it's like it's being blocked.

I also tried to manually input a pre-authentication access url on the acccess controll settings using the url "aps1-omada-cloud.tplinkcloud.com" but we have the same results.

I tried to manually authorize the end device. since we still have the portal link, we refreshed it and it loaded properly.

I think the authentication portal is also being blocked prior to the authentication.

Please help.