Problem with communication between Ignition and PLCs S71200

Good morning from Italy,
I have the following problems with Siemens S7 1200.

I have success in connecting some devices, using the following address type : 192.168.1.XX, with XX that is a number which varies with the device.

I have NOT success connecting devices using 192.168.8.XX.
I suppose the problem is with port 8.
Do you have some ideas about solving this problem ?
Thank you in advance for the answer.

Can you ping the 192.168.8.XX addresses from the server that is running the Ignition gateway?

yes I can ping some of them, unfortunately not all