Error: Exception calling "SynchronizeDirectories" with 6 argument(s): Timeout waiting for WinSCP

Hi,
I am trying to understand the error I received.
I am working on a Synchronization script via Powershell.
I have this working on systems with under 5000 files.
But when there are already over 5000 files I get this timeout error.
Error: Exception calling "SynchronizeDirectories" with "^" argument(s): Timeout waiting for WinSCP to respond".
Could you advise on how to get WinSCP to continue?
I am able to get it to work via the GUI.
I have tried $SessionOptions.Timeout and $SessionOptions.AddRawSettings("SendBuf",0)
Sorry, I am a newbie at this.
Please advise.

Set Session.Timeout to more than the default 1 minute.
https://winscp.net/eng/docs/library_session#timeout