your last capture is showing that you even can't resolve this name at OS level (while you explained the opposite ) thus there is no chance it works using Thunderbird
Could you please post the result of:
ipconfig /all
Windows IP Configuration
Host Name . . . . . . . . . . . . : Titan
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
Ethernet adapter Local Area Connection 4:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : D-Link DFE-538TX 10/100 Adapter
Physical Address. . . . . . . . . : 00-05-5D-42-84-B4
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Ethernet adapter Local Area Connection 3:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Atheros AR8131 PCI-E Gigabit Ethernet Con
troller (NDIS 6.20)
Physical Address. . . . . . . . . : F4-6D-04-D9-2E-E8
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::d84a:cea1:c9dc:f3b7%20(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.42.181(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.42.1
DHCPv6 IAID . . . . . . . . . . . : 435449092
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-15-72-D7-42-00-15-58-24-CC-E0
DNS Servers . . . . . . . . . . . : 192.168.42.1
NetBIOS over Tcpip. . . . . . . . : Enabled