All you want to know about Microsoft 365 new bulk Email Sending method (HVE)

 High Volume Email for Microsoft 365

Last April, Microsoft released the public preview of Microsoft High Volume Email (HVE) for Microsoft 365. HVE is a new service designed primarily for line-of-business applications and other high-volume SMTP Auth submissions, enabling the sending of internal messages beyond the current limits of Exchange Online.

Many customers are using their on-premises hybrid Exchange environments to send bulk emails through email relay, which has become challenging due to Microsoft’s new restrictions. Exchange servers need to be updated, and many customers are struggling to upgrade their existing servers. If customers do not upgrade, Microsoft will throttle their emails.

Current Exchange throttle enforcement stages:

All you need to know about exchange throttling -  https://techcommunity.microsoft.com/t5/exchange-team-blog/throttling-and-blocking-email-from-persistently-vulnerable/ba-p/3815328?WT.mc_id=%3Fwt.mc_id%3DMVP_328457

HVE Current limits

• Pricing has not been release yet but as public preview customer can try on non critical application for email sent. 
• Only 20 HVE account can be create per tenant
• Recipient rate limits is set to 100,000 per day ( per tenant)
• External recipient 2000 per day (Per account)

How to create

1. login to https://admin.exchange.microsoft.com/#/highvolumeemail
2. select "Add an HVE account
3. Provide the basic information and next to finished

Application setting

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

Authentication

During the Preview, High Volume Email (HVE) for Microsoft 365 requires SMTP Basic Authentication. Once it reaches General Availability, OAuth authentication is expected to be supported.
Follow below method to enable basic authentication for HVE account.

1. Connect to Exchange online though PowerShell and run below commend
New-AuthenticationPolicy -Name "allowed basic auth"
Set-AuthenticationPolicy -Identity "allowed basic auth" -AllowBasicAuthSmtp

2. assign to new auth policy to HVE account
Set-User -Identity "HVEaccountName" -AuthenticationPolicy "allowed basic auth"

3. To immediately apply the authentication changes to HVE account run below commend. otherwise it will take up to 24 hours. once you run the commend you can check the within 30 mins.
Set-User -Identity "HVEaccountName" -STSRefreshTokensValidFrom $([System.DateTime]::UtcNow)

Usage Reports

Navigate to https://admin.exchange.microsoft.com/#/reports/highvolumeemaildetails