Mqtt on a remote server

Configuration
1

Hello
Machine No. 1:
A home assistant has the IP address 192.168.1.148
MQTT is operational on this machine.

Machine No. 2:
I installed Home assistant on this machine
and I want to reach the MQTT server of the machine
with the IP address 192.168.1.148.
So I enter in the options the IP address and the login
which allows me to connect to machine No. 1.
I then have the message CONNECTION ERROR.
Can someone help me?

2

Should work. Are they on the same network ? No firewall active ?