Manage high volume emails for Microsoft 365 Public preview

Important

High volume email (HVE) service is currently in public preview and subject to change. We reserve the right to suspend or disable the service at any time if we detect any misuse or abuse of the service by any user. We appreciate your understanding and cooperation in this matter.

HVE is mainly for internal mass communication, and we have a limit of 2k external recipients per day. Please note that any efforts to bypass this limit will be noticed and such email will not be delivered.

Here's the comparison of options to send email using Microsoft 365 or Office 365 for multifunction device or application:

Features	SMTP client submission	SMTP relay	Microsoft 365 High Volume Email
Send to recipients in your domain(s)	Yes	Yes	Yes
Relay to internet via Microsoft 365 or Office 365	Yes	Yes	Limited*
Bypasses antispam	Yes, if the mail is destined for one of your Microsoft 365 or Office 365 mailboxes.	No. Suspicious emails might be filtered. We recommend a custom SPF record.	Yes, if the mail is destined for one of your Microsoft 365 or Office 365 mailboxes.
Supports mail sent from applications hosted by a third party	Yes	No	Yes
Saves to Sent Items folder	Yes	No	No
Open network port	Port 587 or port 25	Port 25	Port 587
Device or application server must support TLS	Required	Optional	Required
Requires authentication	Microsoft 365 or Office 365 username and password required	One or more static IP addresses. Your printer or the server running your Line of Business (LOB) app must have a static IP address to use for authentication with Microsoft 365 or Office 365.	Office 365 HVE account username and password

For detailed comparison see: How to set up a multifunction device or application to send email using Microsoft 365 or Office 365 | Microsoft Learn.

Note

A few additional notes around authentication:

• If Security Defaults is enabled, all basic authentication including SMTP is disabled, making High Volume Email (HVE) non-functional.
• HVE accounts can operate even if SMTPClientAuthenticationDisabled is set to True within TransportConfig, due to the use of the custom endpoint.
• To avoid any impact from authentication policies, it's important for customers to ensure AllowBasicAuthSmtp is enabled in their organization for the HVE account. Custom authentication policies can be applied to the HVE accounts as needed.

Public preview limitations and known issues:

• Up to 100k recipients per 24 hrs.
• Up to 20 HVE accounts.
• HVE accounts are different kinds of mail user accounts. Please avoid giving any license to HVE accounts.

Get started with High Volume Email service

Create an HVE account

1. Navigate to https://admin.exchange.microsoft.com/.

2. Under the Mail flow menu, select High Volume Email(Preview).

   

3. Select Add an HVE account.

   

   

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

   

5. Select Next.

   

6. Validate provided information.

7. Select Create.

8. The new HVE account is listed in the HVE accounts list.

View HVE usage report

1. Navigate to https://admin.exchange.microsoft.com/.

2. Under Reports, select Mail flow.

3. Under listed Mail flow reports, select High Volume Email (Preview).

   

4. Report shows usage data for the tenant for the selected period.

5. Select specific Sender address to view usage data for this account for selected period.

   

6. To see how much each HVE account uses, choose an account from the list.

   

7. To get detailed information about messages that are sent from your HVE, select Request report.

8. Enter the Start date, End date, and Recipients to identify email addresses of users who will receive requested report. If you enter value in the HVE account field, you'll get detailed report only for this specified HVE account.

9. Select Request.

   

PowerShell account management

To connect to Exchange Online PowerShell, see Connect to Exchange Online PowerShell.

Display all HVE accounts

To display all existing HVE accounts, run the following command:

Get-MailUser -LOBAppAccount

This command returns the following data:

Create HVE account

To create HVE account, use one of the following methods:

• Provide the account and password:

  $securePassword = Read-Host "Enter password" -AsSecureString
  
  New-MailUser -LOBAppAccount -Name "HVEAccount01" -Password $securePassword -PrimarySmtpAddress "HVEAccount_01@contoso.com"
  

• Provide the account and be asked to enter the password:

  New-MailUser -LOBAppAccount -Name "HVEAccount01" -PrimarySmtpAddress "HVEAccount_01@contoso.com"
  

  You'll receive confirmation of the HVE account creation:

  

• Be asked to enter the account and password:

  New-MailUser -LOBAppAccount -PrimarySmtpAddress "HVEAccount_01@contoso.com"
  

  

Note

For the Public preview release, you can create up to 20 HVE accounts for the tenant.

Remove HVE account

To remove HVE account, run the following command:

Remove-MailUser -Identity "HVEAccount_01"

You need to confirm that you would like to remove this account.

Change display name

To change display name, run the following command:

Set-MailUser -LOBAppAccount -Identity "HVE account" -DisplayName "HVE account 2"

Fix issues with High Volume Email for Microsoft 365

I set up my printer or LOB app for HVE, but it still can't send email

1. Check the settings that were entered directly into the printer:

   Printer setting	Value
   Server/smart host	smtp-hve.office365.com
   Port	Port 587
   TLS/StartTLS	Enabled
   Username/email address and password	Sign in with credentials of HVE account

2. Your printer or application must send email from the same email address that you entered as sign-in credentials during email setup.

3. Check if username and password are correct.

4. Validate that your HVE account and service is working correctly. You can use SMTP component in the Power Automate platform: SMTP - Connectors | Microsoft Learn.

Error: Authentication unsuccessful

If you receive one of the following errors:

• 535 5.7.3 Authentication unsuccessful
• 535 5.7.139 Authentication unsuccessful, the organization configuration doesn't allow this authentication request.

1. Disable the Azure Security Defaults by toggling the Enable Security Defaults to No:

   • Sign in to the Azure portal as a Security administrator, Conditional Access administrator, or Global administrator.
   • Navigate to Microsoft Entra ID > Properties.
   • Select Manage security defaults.
   • Set the Enable security defaults toggle to No.
   • Select Save.

2. HVE accounts can operate even if SMTPClientAuthenticationDisabled is set to True within TransportConfig due to the use of a custom endpoint.

3. To avoid any impact from authentication policies, if these are being utilized, it's important for customers to ensure AllowBasicAuthSmtp is enabled in the policy that applies to the HVE account. Custom authentication policies can be applied to the HVE accounts as needed.

Following are the suggested practices when you receive errors:

• Do you know your recipients? Manage them with a (static, flat) DL and use the service to send message to one recipient: the DL.
• You have many recipients and they change too frequently? Use AD tags with a DDL. Use the service to send message to one recipient: the DDL.
• You can't rely on DLs? Send flat listed recipients batched using the maximum recipient limit (50).
• Do you need to send to a single recipient? Maintain the SMTP session and send messages one-by-one.