Sending bulk emails from Powershell script

Abdullah Tahir khan 61 Reputation points

Hi there,

I need to know does Office365 allow to send bulk email from Powershell. I have tried Powershell script but no avail.
I have got below errors in Powershell after running the script;

Sending Notification to (emailaddress@keyman .com)
Exception calling "Send" with "1" argument(s): "Error in processing. The server response was: 5.7.3 STARTTLS is
required to send mail []"

Any help please.

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
4,373 questions
Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,492 questions
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Accepted answer
  1. Andy David - MVP 145.1K Reputation points MVP

    You have to send using TLS 1.2:

    BUT - Sending Bulk Mail mail though Office 365 is not allowed:

    Recipient rate limit: To discourage the delivery of unsolicited bulk messages, Exchange Online has recipient limits that prevent users and applications from sending large volumes of email. These limits are applied per-user to all outbound and internal messages.


    Exchange Online customers who need to send legitimate bulk commercial email (for example, customer newsletters) should use third-party providers that specialize in these services.

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1 additional answer

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  1. KyleXu-MSFT 26,241 Reputation points

    @Abdullah Tahir khan

    Here is also a related thread which said using command below to force Send-MailMessage to use TLS 1.2 :

    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12  

    Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

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