Hello Alex, From logs which you pasted in appear that you can ping 192.168.1.10& 192.168.1.105 from vlan 10 whose IP is 192.168.1.253 i.e same subnet However you cannot ping  192.168.1.105 from vlan 20 whose ip is 10.230.36.253 i.e different subnet....

Hello, you need to enable routing between SVI's. configure "ip routing" command on L3 switch..

Hi, Have  you try to change duplex settings on router B, it seems it is configured to FULL, can you change duplex to auto.