1864 does work, but why aren’t you using 1863? Anyway, your issue right now is with authentication.
With these third-party clients work differently from Messenger and you won’t be able to strictly use Escargot patching documentation to make them work. For instance, in soap.cpp, you’ll need to replace login.live.com with m1.escargot.log1p.xyz, as that’s what (presumably) is doing the login and you’ll be hitting the real Microsoft account server otherwise.
Some alternative suggestions you might consider:
- Per this post: aMSN with Escargot Support?, aMSN can be made to work already, albeit with some sort of memory leak problem. I had forgotten about this, but it may work differently now since there’s been server changes since, or you might be able to figure out what’s causing the leak. It’s in tcl so you don’t need to keep compiling it.
- You could try modifying emesene, which is my favourite third-party Messenger client. It’s in python, so you can also mess with it easily.
- You can also try modifying libpurple’s msn-pecan plugin instead. It was the most popular option during the same time as the current Messenger versions used right now. However, I did try making it work myself and had no luck getting past authentication, but I wasn’t dealing with the source and haven’t gone as far as to do any real debugging.