It took me some time to figure out. But I finally managed to get the right things together. Some sources stated that it is impossible to do this with Powershell, because it supposedly doesn’t support TLS. Apparently, the current Powershell version supports SSL/TLS. There were various templates on the internet that saved the encrypted password in a file. Which is a safer method than storing the password in the Powershell script file. I wanted to show you how to do this without much hassle.

# Encrypt the password
$encryptedPassword = ConvertTo-SecureString “MyUnencryptedPassword” -AsPlainText -Force

# Create a credentials object with the e-mail and password
$mycreds = New-Object System.Management.Automation.PSCredential (“yourlogin@mydomain.onmicrosoft.com”, $encryptedPassword)

# Send the e-mail (should take less than 5 seconds)
Send-MailMessage -To "receiver@domainname.com" -SmtpServer "smtp.office365.com" -Credential $mycreds -UseSsl "Hello World" -Port "587" -Body "Hello World,<br/>This is your first e-mail<br/>Kind regards,<br/><br/>Your Support Bot" -From "yourlogin@mydomain.onmicrosoft.com" -BodyAsHtml

Your login or e-mail can also be replaced by the actual e-mail of the company, which would have been in my case firstname.lastname@domain.com. You don’t need to necessarily include the ‘onmicrosoft.com’ part.