Powershell script works in Powershell but fails in Task Scheduler

I have a PowerShell script that sends an email via SMTP. The script runs fine inside Powershell ISE, but fails in Task Scheduler. I am on Windows Server 2012. I have other Powershell scripts that I run on this server using the exact same setup, but those scripts do not send an email. The return code I see in Task Scheduler is (0xFFFD0000) and I cannot find any information on this. I have the task set to run with highest privileges and I have checked that the executionpolicy is RemoteSigned. Anybody run into this before?

Here is the command in the task:

powershell -f "c:\scripts\EmailTest.ps1"

Here is the script:

$EmailFrom = "user@domain.com"
$EmailTo = "someone@somewhere.com"
$Subject = "Email Subject" 
$Body = @"
Person,

Some message here

Thanks,
User
"@

$SMTPServer = "smtp.domain.com" 
$SMTPClient = New-Object Net.Mail.SmtpClient($SmtpServer, 25) 
$SMTPClient.Credentials = New-Object System.Net.NetworkCredential("user@domain.com", "password"); 
$SMTPClient.Send($EmailFrom, $EmailTo, $Subject, $Body)

Update: I was able to resolve the issue. Apparently I had an additional line in the script that was commented out. I'm not sure why this would cause an error but once I removed that commented out line it ran fine in Task Scheduler. the comment looked like this and was just below the other $EmailTo declaration in the above script:

#$EmailTo = "someone@somewhere.com"

I found another possible issue while looking at a similar problem. I was unable to execute a PowerShell script as a Task Scheduler action, even though the script ran correctly when logged into Windows as the target user and running within PowerShell.

Task Scheduler would consistently display the 0xFFFD0000 error when I nominated the script in the task's action arguments using what I believed to be normal PowerShell quoting rules:

-ExecutionPolicy Bypass -File 'D:\full path\to\script.ps1'

PowerShell acquiesced and Task Scheduler fired off the task immediately and without issue when I changed the quotes I used from single to double:

-ExecutionPolicy Bypass -File "D:\full path\to\script.ps1"

Dropping to a command prompt and executing the full command immediately revealed the problem:

D:\>C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -ExecutionPolicy Bypass -File 'D:\full path\to\script.ps1'

Processing -File ''D:\full path\to' failed: The given path's format is not supported. Specify a valid path for the -File parameter.

Notice the strange use of two single quotes before the path and one single quote after.

The moral of the story: When feeding the full path of a script to PowerShell as a command line parameter, use double quotes!