[9.1] Trade to NPC not working

[island212]

Steps to reproduce

Say hi to a NPC

Expected behaviour

NPC chat window open in the chat box and you can write trade for a window to popup to buy and sell to the NPC.

Actual behaviour

Nothing happen and I get this error in my console everytime I say hi to a NPC

ERROR: Unable to send extended opcode 1, extended opcodes are not enabled
ERROR: ProtocolGame parse message exception (66 bytes unread, last opcode is 170, prev opcode is 170): InputMessage eof reached

Environment

Client 0.6.6 on 9.1 server
Compile myself using Visual Studio 2019 Community
Windows 10

The visual studio project wasn't compiling so I used #1073 to fix it

[island212]

I found this issue but the proposed fix has already been merged #743

[peonso]

Correct fix should be something similar to this #1119, the correct messageModsMap need to be checked for protocol 9.1.