Why is the subnet not available?

Question

Mikrotik

There is an office Mikrotik, which has a native subnet 192.168.100.0/24 . A network cable is plugged into one of its ports, which provides subnets 192.168.200.0/24 and 192.168.234.0/24 at the same time.
Subnet 192.168.200.0/24 was registered before me . When I ping her computers from the 192.168.100.0/24 subnet , the ping goes on, the computers are available. But when I ping computers on the 192.168.234.0/24 subnet from the 192.168.100.0/24 subnet , the ping fails. Although if you ping the subnet 192.168.234.0/24 from Mikrotik itself , then the pings go.
For both subnets 192.168.200.0/24 and192.168.234.0/24 on Mikrotik, in the IP > Addresses section, gateways 192.168.200.254 and 192.168.234.254 are registered, respectively:

/ip address
add address=192.168.200.254/24 interface=ether2
add address=192.168.234.254/24 interface=ether2

Also, in the IP > Routes section there are dynamic routes for these subnets. They were created automatically.
Nothing else is written on Mikrotik. Neither NAT nor firewall.
How can this be? Why is one subnet available from my LAN and the other is not? On Mikrotik, the settings for both of these subnets are the same.

Answer 1

On computers in the subnets 192.168.234.0/24 and 192.168.100.0/24, Mikrotik must be registered as the default gateway.