Managing High Volume Emails through M365: Public Preview

High volume email (HVE) service is used for sending mass mail communication. In general there is a limit of 2k external recipients per day. These limits depend on two specific volatiles: 1) Recipient Rate Limit, 2) Message Rate Limit. HVE helps customers to enable and go beyond these outbound limits.

• Recipient rate limits can prevent users and applications from sending large volumes of messages. The recipient rate limit for all licenses highlighted in green in the above table will remain at 10,000 recipients per day per tenant, which will apply per-user to all outbound and internal messages.
• Message rate limits explain how many emails a user is able to send via SMTP from Exchange Online within a specific period. When outbound message volumes exceed the message rate limit, excess message submission will be throttled and successively carried over to the following minutes.

In the public preview, the cost is free and yet there is a limit upto 100,000 recipients per day per tenant. These limits will be expanded at General Availability, Microsoft will provide tenant admins with capabilities to set the volume threshold themselves as a per-account basis so that admin can control the volume.

HVE details:

HVE allows users to create Mail Users (up to 20 during the preview) in Exchange Online, so that they can send messages using a specific SMTP endpoint.

The public preview includes an Exchange admin center to manage HVE accounts, a report to track the usage, and an SMTP endpoint using basic SMTP auth to send email.

The public preview will induct some limits, which will be extended at General Availability:

Public preview limitations:

• Up to 100k recipients per 24 hrs.
• Up to 20 HVE accounts.

Service information

• Server/Endpoint: smtp-hve.office365.com
• Port: 587
• TLS: STARTTLS
• TLS 1.2 and TLS 1.3 are supported
• Authentication: Username and password

Authentication:

The High Volume Email (HVE) for Microsoft 365 requires SMTP Basic Authentication, during the preview period. Once it reaches General Availability the OAuth authentication will be expected to be supported.

Some notes regarding authentication:

• If “security defaults” is enabled, all basic authentication, including SMTP is disabled, making HVE non-functional.
• HVE accounts can operate even if SMTP Client Authentication is in Disable state within Transport Configuration due to the use of a custom endpoint.
• To avoid any impact from authentication policies, if these are being utilized, it is important for users to ensure the SMTP basic Authentication is enabled in the policy that applies to the HVE account. Custom authentication policy can be applied to the HVE accounts as needed.

Create an HVE account

• Go to exchange admin center
• Under the Mail flow setting, click High Volume Email(Preview)

• Then click Add an HVE account.

• Put a display name and Primary address should be in the following format: username@domain.com, where domain.com should be within a list of accepted domains, alias (optional), and password.

• click Next
• then Create
• The new HVE account is created in the HVE accounts list.

How to view HVE usage report

• Go to Exchange admin center
• Expand Reports, click Mail flow
• Under the Mail flow reports, click the radio button for High Volume Email (Preview).

• Report will show the usage of data for the tenant for the selected period of time
• Select specific Sender address to view usage data report for this account.

• If you want to view how much data each HVE account uses, then select an account from the reported list.
• If you want to get details report, select Request Report, enter the required details and then click Request