i wanted to downgrade from 7.5 to 4.7 but then i discorved it didnt wanted, it pretended that my password was WRONG, weird. my msn wasnt hacked at all, so why it says that the password was wrong? i even enabled the legacy support and patching it but that didnt worked.
When you signed up your email, did you have this checkbox checked?
Cause if you haven’t then it won’t work in the mentioned versions. and 4.7 is one of them.
well, i enabled it (but now i disabled it since i was using 5), but that didnt worked, (was using a windows 7 virtual machine)
Make another email with it enabled.
i was having a similar problem where i couldn’t sign in to ver 4.7 but i could sign 5.0 using the same account (yes i did patch the registry and check the checkbox and i still haven’t fixed it) 
Windows Messenger only worked with me with MSN swither ( the patched version no work )