It is fairly easy to send emails with PowerShell. For that purpose, there is the built-in cmdlet Send-MailMessage, which Microsoft now describes as deprecated:
⚠️ Warning
The Send-MailMessage cmdlet is deprecated. This cmdlet does not guarantee secure connections with SMTP servers. Although there is no immediate replacement available in PowerShell, it is recommended not to use Send-MailMessage. For more information, see Platform Compatibility Note DE0005.
Source: https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/send-mailmessage?view=powershell-7.5
For some scenarios, using Send-MailMessage is still okay in my opinion. For example, if you run your own SMTP server, such as a Microsoft Exchange Server, or you have one hosted somewhere else, there is often no support for modern authentication methods. Of course, you could also run such an SMTP server in addition to an Exchange Online environment. In general, I would recommend using a subdomain such as “reports.demotenant.de” rather than just “demotenant.de” for these automated emails, but that is not a requirement.
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