Powershell script via task scheduler not work as expected

machineslave 

If the same commands work fine from normal powershell console and if you face issue only in Task Scheduler, then the problem might be the user account that you have configured for the schedule task.

The command Send-MailMessage accepts the parameter -Credential. If you don't provide this parameter, then the command runs in the current user privilege. In your case, the account that you set in the schedule task ( Task -> Properties -> General tab -> Security Option -> When running the task, use the following account).

But I would recommend you to store your credentials in Windows Credentials Manager and retrieve it using PowerShell and use it in Send-MailMessage command.

Store Credentials

Install-Module -Name CredentialManager
New-StoredCredential -Target "MyUserInfo" -UserName "username" -Password "mypwd"

Read the stored user credential from Windows Credentials manager

$psCred = Get-StoredCredential -Target "MyUserInfo"

You can change your script as shown in below command

Send-MailMessage -From "o365.service.eu@mydomain.com" -To stefan@mydomain.com -SmtpServer smtp.mydomain.com `
-Subject "Added picture for $mailAddress" -Credential $psCred

For this line : Start-Transcript -Path "transcript.txt" -Append (ne), provide complete path :

Start-Transcript -Path "C:\\LogFiles\transcript.txt"

Same for other paths:

$date2 = $date.ToShortDateString() + " - " + $date.ToShortTimeString()
$date2 + " - Uploaded picture for " + $mailaddress | "C:\\LogFiles\log.txt" -append