Refer to the exhibit.
Switch# show ip interface brief
Interface IP-Address OK? Method Status Protocol
Vlan 1 172.19.1.250 Yes manual up up
FastEthernet0/1 unassigned Yes unset up up
FastEthernet0/2 unassigned Yes unset up up
FastEthernet0/3 unassigned Yes unset up up
The network administrator normally establishes a Telnet session with the switch from host A. However, host A is unavailable. The administrator's attempt to telnet to the switch from host В fails, but pings to the other two hosts are successful. What is the issue?