WinSCP re-authenticates on file save with OTP, but works correctly via SSH port forwarding

Hi,

I am experiencing an issue when using WinSCP with a server that requires a password and a verification code for authentication.

Steps to reproduce:

• Connect to the server using WinSCP.
  
• Enter the password and verification code.
  
• Login succeeds.
  
• Open a remote file and edit it (tested with both the internal editor and an external editor).
  
• Save the file.
  

At this point, WinSCP prompts for the verification code again. If I continue editing and saving files within a short period of time, eventually the connection fails with:

No supported authentication methods available

Thanks you get an OTP prompt for the first save is expected, as edited files are uploaded using a separate connection. For the "No supported authentication methods available" problem, please post session log file.