Maybe some software that checks and controls ports (for example VPN, [employee monitoring software]proxy) closed this port for its needs?

Good afternoon
So I've got a large scale tool changer, and I've been trying to get all my tool selection gcode tweaked to work really well.
So now that I've tested a tool selection, the machine goes through ""tpre0.g"" as it should, but doesn't actually change the status of tool from 0 to active.
And if I send another T0, the ""tpre0.g"" returns.
Running 3.1.1 on Duet 3 with 3 tool boards and two external drivers.
Regards