Problem with exchange with CAS scales on some computers?

Question

Computer networks

There is a self-written c# program that connects to CAS LP 15 ver 1.6 trading scales using a driver from the manufacturer. On my computer (Win 8.1 Pro 64bit latest updates, in a virtual machine), the connection and exchange with the scales pass without errors. Also at home there is an Asus eeepc netbook with Win 10 Pro 32bit build 1703 on which the connection also goes without problems. There are 2 laptops in the store with Win 10 Pro build 1803 64bit, on which the same program sometimes cannot connect to the scales, and the transfer of data to the scales without errors is even less common. The latter have Kaspersky free and Avast antiviruses installed, respectively. The last one is at my house.
Avast removed, the firewall turned off, turned on and prescribed exceptions and allowing rules where possible, changed the port from native 8111 to 5511.

Answer 1

Judging by the fact that you indicate the port numbers, the exchange with the scales is via Ethernet.
Accordingly, there may be typical problems with the network.
For the test, run a ping on the scales, see if there are packet losses, what is the response time.
If there are losses, then you need to check the entire path from the scales to the computer: cables, sockets, connectors, routers.
It would be nice to have a network specialist take over the network check.
Check the driver version, compare it with the one on the running machine.
If the scales are different, then check the firmware version of the scales.