powershell-send-email-via-ms-outlook-365-with-attachments

powershell-send-email-via-ms-outlook-365.ps

$who = New-Object System.Management.Automation.PSCredential(
        "account@domain.there", 
        (ConvertTo-SecureString "TheSecret" -AsPlainText -Force)
      ) -ErrorAction Stop; 
#NOTE: this version of Send-MailMessage does NOT have a -ReplyTo parameter.
Send-MailMessage `
            -From account@domain.there `
            -Subject $("{0} Reports, dd. {1}" -f $files_count, $now) `
            -To undisclosed recipients `
            -Body $([System.String]::Concat(
                    "Please find attached your $($files_count) report$($plural_s):  `r`n  `r`n",
                    ($files -Join ",  `r`n"),
                    "  `r`n  `r`n",
                    "--  `r`n",
                    "For support and feedback, contact account@domain.here.  `r`n"
                  )) `
            -Attachments $files.ToArray([System.String]) `
            -Port 587 `
            -SmtpServer smtp.office365.com `
            -UseSsl `
            -ErrorAction Stop `
            -Credential $who;

It took a while to figure out how to send emails via Microsoft Outlook 365. This largely is Microsoft's fault, for refusing to adhere to standard SMTP practices. Salient points here are the port number (587), the SMTP server address, and the switch to use SSL.

Important too is the use of a specific PSCredential object. Its authentication must be set to an existing pre-qualified email user account. Additionally, to prevent your emails from getting blocked by Microsoft's spambot blocker, tell your Office 365 mail settings to allow that user account to be used as an emailer / from address.

Warning: using automated emailers may get your domain blocked and blacklisted by spam blockers. Be courteous.