When using the FQDN of linux host, I was able to accept the keys and the password prompt came up. Immediately hit cancel and then tried again, then a Microsoft Visual C++ Runtime Library.
Program D:\\Prgram Files (x86)\WinSCP\WinSCP.exe
For information on how your program can cause an assertion failure, see the Visual C++ documentation on asserts
(Press Retry to debug the application - JIT must be enabled)