Why do computers on the 2nd and 3rd floors not see the server?

Question

TP Link

The hospital has a network, the first floor has ip range 192.168.0.255-192.168.0.255, and server 2003 has ip 192.168.0.111, also adsl modem with ip 192.168.0.1, on the second floor computers with ip 192.168.100.1-192.168.100.255 and adsl modem with ip 192.168.100.1, and on the third floor 192.168.200.1 with adsl modem with ip 192.168.200.1. why the computers of floors 1-2-3 cannot see each other, and the computers of floors 2-3 cannot connect via RDP to server 2003. not all computers have a static address.
If on the computer of the 3rd floor you check the box to issue ip automatically, then you can get the ip and the server of the first or 2nd floor.

Answer 1

Are the networks physically connected?
Communication between "modems" - is there?
Why does the first floor have a range of 192.168.0.255-192.168.0.255? (Ochapyatka?)
As I understand it, you have the following scheme:
1st floor - 192.168.0.0/24, gateway 192.168.0.1
2nd floor - 192.168.200.0/24, gateway 192.168.200.1
3rd floor - 192.168.300.0/24, gateway 192.168. 300.1
But proceeding from described by you "If on the computer 3... SP and the server of the first or 2 floors."
Then their switches are connected, and DHCP is enabled on each gateway. And on gateways (modems / routers), routing between subnets is not configured.
Answer the question "How many computers do you have?". If not very much, then it makes sense to leave one "modem" and give everyone an IP of the same range. For example 192.168.0.1/24.
But with such questions, it is better to contact a specialist before anything is broken.
UPD 1:
If there are a lot of computers, then I see the following options:
Divide each network into different Vlans and give each Vlan its own IP range. This requires a good router.
A more budget solution is:
Three networks (IP I choose for a simplified calculation):
1st floor - 192.168.100.0/24, gateway 192.168.100.1
2nd floor - 192.168.200.0/24, gateway 192.168.200.1
3rd floor - 192.168.300.0/24 , gateway 192.168.300.1
On the first floor, where the server is, this is the main network, the router leads to the Internet.
On the second floor, the switches should be reduced to router 2.
On the third floor, the switches should be reduced to router 3.
On router 2 and 3, NAT must be up on one of the ports that go to the first floor switch. And register redirection to the server on port 1189 on them. Then, on the computers of the second and third floors, you need to connect via RDP to 192.168.xxx.1:1189.
But here it is important that your routers (aDSL modems) support all this pornography.
It’s hard to explain on nightingales, in general, a simplified scheme:

Answer 2

I already wrote, if you put the Ip address automatically, you can get the address of any of the networks of the 1st or 2nd or 3rd floors.

Answer 3

In general, from the description, I realized that your network is wrong, and in theory you need to change the topology. Three DHCP servers are terrible. But you can of course help if you manually register an IP server from all three ranges, then all three networks will connect to it via rdp.
In general, change the network topology before big problems start.