Sporadic error code 2 while getting files from SFTP server

param([string] $hostname,
    [string] $username,
    [string] $password,
    [string] $source,
    [string] $destination
)
 
# Set log file
$scriptname = ([System.IO.FileInfo]$MyInvocation.MyCommand.Definition).BaseName
$logfile = "$PSScriptRoot\$scriptname.log"
 
# Log function
Function LogWrite
{
    param([string] $logstring)
 
    Add-Content $logfile -value $logstring
}
 
try
{
    # Load WinSCP .NET assembly
    Add-Type -Path "WinSCPnet.dll"
 
    # Setup session options
    $sessionOptions = New-Object WinSCP.SessionOptions -Property @{
        Protocol = [WinSCP.Protocol]::Sftp
        HostName = $hostname
        PortNumber = 2222
        UserName = $username
        Password = $password
        SshHostKeyFingerprint = "*******"
    }
 
    # Create session
    $session = New-Object WinSCP.Session
 
    try
    {
        # Connect
        $session.Open($sessionOptions)
 
        # Find files older than 3 minutes
        $directoryInfo = $session.ListDirectory($source)
        $limit = (Get-Date).AddMinutes(-5)
        $readyFiles =
            $directoryInfo.Files |
            Where-Object { -Not $_.IsDirectory } | 
            Where-Object { $_.LastWriteTime -lt $limit }
        
        # Set transfer options
        $transferOptions = New-Object WinSCP.TransferOptions
        $transferOptions.TransferMode = [WinSCP.TransferMode]::Binary
        $transferOptions.OverwriteMode = [WinSCP.OverwriteMode]::Overwrite
        
        foreach ($readyFile in $readyFiles)
        {
            # Download files
            $transferResult = $session.GetFiles($session.EscapeFileMask($source + "/" + $readyFile.Name), $destination, $True, $transferOptions)
            
            # Throw on any download error
            $transferResult.Check()
     
            # Log download results
            foreach ($transfer in $transferResult.Transfers)
            {
                LogWrite ("{0}: Download of {1} succeeded" -f (Get-Date), $transfer.FileName)
            }
        }
    }
    finally
    {
        # Disconnect, clean up
        $session.Dispose()
    }
 
    exit 0
}
catch [Exception]
{
    LogWrite ("{0}: {1}" -f (Get-Date),  $_.Exception.Message)
    exit 1
}