Hope This Helps

E-Mail senden über Office 365 mit der Powershell

[System.Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
 
 $PWD = 'YOURPASSWORD' | ConvertTo-SecureString -AsPlainText -Force 
 $USER = New-Object System.Management.Automation.PSCredential ("USERLOGIN", $PWD)

 $Para = @{
    SmtpServer = 'smtp.office365.com'
    UseSsl     = $true
    Port       = '587' 
    Credential = $USER
    Body       = 'TESTMAIL' 
    To         = 'EMPFÄNGERADRESSE'
    From       = 'SENDERADRESSE' 
    Subject    = 'Testmail'
} 
 
Send-MailMessage @Para