Help setting up a home network

Question

Computer networks

Hi guys. Can't set up home grid. The situation is this - on the second floor there is a router ZTE ZXDSL 831 Series( ), which distributes the Internet with static IP addresses. A switch is connected to it. A router, computer A ( ) and a long twisted pair cable that goes to the first floor are connected to the switch. Computer B ( ) was connected on the first floor , which works fine in this situation. Now computer C ( ) has appeared next to computer B. Therefore, a switch is installed on the ground floor , which was connected to , and to which B and192.168.1.1
Surecom EP-805SX-C
192.168.1.2192.168.1.3

192.168.1.4Palm A 500SurecomB . Naturally, nothing worked. Computers B and C do not see the router and computer A , but they see each other. I assumed that the point is that you need a crossover, and not a straight cable to connect the switches (d), but when I installed the crossover, nothing has changed.

Here is the diagram:

If the cable (d) is plugged into computer B or C directly, then the Internet will appear on the corresponding computer.

I doubt that this is important, but the computers have the following operating systems:
A - Kubuntu
B - OpenSuse C
- Windows 7

In general, I count on advice. And, if possible, without additional purchase of equipment and without transferring the router)
Thanks in advance)

upd:
maybe it's a small adapter. I have a long cable straight, I connect a crossover cable to it, and then a switch:

in a normal situation, cable B is connected through an adapter to cable (d) and it works.

Answer 1

Start diagnostics with L1
1. Do the lights on the switches light up when you plug in a long wire? (You said the cable is long, maybe PALM is just less long-range than the computer networker)
2. Maybe the port on PALM is dead, try another one.
3. As g0dlike said, try swapping the switches
. The ideology of the network is correct anyway.

Answer 2

The diagram is correct.
It is not clear what is meant by "do not see". How was it diagnosed?
I recommend collecting all the junk in one room and connecting it with short but obviously reliable patch cords. So we will exclude the cable industry from suspicion. If it doesn’t work, then we exclude the switches from the circuit one by one, first one, then we substitute the other. That way we'll find out who's the goat.