Problem executing REMOTE powershell script using WinSCP via SQL Server Agent Job

On SQL Server 2016 I have setup a job that executes a powershell script that resides on a remote app server. When I execute the powershell script via the app server using the Powershell ISE app my script works without issue. When I had setup the job and enter this command:

powershell.exe -ExecutionPolicy Bypass -file "\\serverapp1\c$\coverageverifier_scripts\SFTP_CoverageVerifier.ps1" in Step 1.

When I look at the VIEW HISTORY I see the error below but I cannot figure out why the script now cannot load the file or assembly.

Any help/direction would be appreciated. Here is the error:

The job script encountered the following errors. These errors did not stop the script: A job step received an error at line 1 in a PowerShell script. The corresponding line is 'powershell.exe -ExecutionPolicy Bypass -File "\empqaapp1\c$\coverageverifier_scripts\SFTP_CoverageVerifier.ps1"'. Correct the script and reschedule the job. The error information returned by PowerShell is: 'Add-Type : Could not load file or assembly '

Here is my powershell script as well:

# Load WinSCP .NET assembly
#Add-Type -Path "WinSCPnet.dll" 
Add-Type -Path (Join-Path $PSScriptRoot "WinSCPnet.dll")

# Declare variables 
$date = Get-Date
$dateStr = $date.ToString("yyyyMMdd")

# Define $filePath
$filePath = "C:\coverageverifier_scripts\TEST_cvgver.20190121.0101"

# Write-Output $filePath

# Set up session options for VERISK TEST/ACCEPTANCE SFTP SERVER
$sessionOptions = New-Object WinSCP.SessionOptions -Property @{
    Protocol = [WinSCP.Protocol]::Sftp
    HostName = "secureftpa.iso.com"
    UserName = "account"
    Password = "pw"
    SshHostKeyFingerprint = "ssh-rsa 1111 xxx/xxxxxxxxx+3wuWNIkMY5GGgRObJisCPM9c9l7yw="
}

$session = New-Object WinSCP.Session 
$session.ExecutablePath = "C:\WinSCP\WinSCP.exe"

try
{
    # Connect
    $session.Open($sessionOptions)

    # Transfer files
    $session.PutFiles($filePath,"/").Check()
}
finally
{
    $session.Dispose()