My AP 55C doesn't work on my 172.16.x.x network

Hello, i created this topic to get some help.

We have 2 differents network, 192.168.x.x and 172.16.x.x, my AP 55C work into the 192.168.x.x network but not into 172.16.x.x network.

How can i establish the connection between AP 55C into 172.16.x.x network and my UTM which it's into 192.168.x.x.