Hi gurin .
You need to check the connection, kindly make sure Lan cable plug in port 4, and 2 light on your stb, red for standby mood and green for switch on. Then you may try to clear the STB cache in the setting menu. Than off/on the STB and rety. However if the issue persist, you may refer to unifi support for further assistance.
They can be reach thru several channel, you may check their website at https://home.unifi.com.my/support/contact-us