Microsoft Drops Bulk Email Rate Limits in Exchange Online

Microsoft revealed today that it will no longer be limiting Exchange Online bulk email senders to 2,000 external recipients per day.

Microsoft’s intention to implement a new Mailbox External Recipient Rate Limit (ERR limit) of 2,000 receivers per user/mailbox within a 24-hour period in Exchange Online has been permanently cancelled. The decision was made on yesterday, following strong criticism from clients who said the cap would make operations difficult.

The current Exchange Online limits are still in effect even though the specific mailbox ERR limit was eliminated. Microsoft highlights that businesses that require this feature should utilise a specialised service because Exchange Online is not intended for high-volume mass email.

The update was first unveiled in April 2024, when Microsoft said it would roll out External Recipient Rate (ERR) limits in January 2025 as an anti-spam measure, and begin enforcing them for existing cloud-based mailboxes from July through December 2025.

This new Mailbox External Recipient Rate Limit was created for the purpose to stop Microsoft 365 users from misusing Exchange Online resources and to limit unfair usage, as was detailed last year.

However, in response to unfavourable consumer feedback, Microsoft declared on Tuesday that the Exchange Online bulk emailing rate cap will be permanently removed.

“Given the restricted capabilities of bulk sending services now available, customers have reported that this limit poses substantial operational issues. The Exchange Team stated, “We value your input and are dedicated to finding solutions that strike a balance between security and usability without creating needless disruption.”

But we intend to deal with these problems in a way that doesn’t interfere with your company’s operations. This calls for more intelligent, flexible strategies that respect your operational requirements while safeguarding the service.

Exchange Online enforces a Recipient Rate limit of 10,000 recipients and a Tenant External Recipient Rate Limit of 5,000 external recipients per day, which will not alter, even though it does not permit sending vast amounts of email from a single account.

As mandated by new guidelines since April 2024, Google is also strengthening its defences against spam and phishing assaults by automatically banning emails from bulk senders who authenticate their communications and don’t exceed tighter spam levels.

Those who need to send more than 5,000 messages daily to Gmail accounts are need to set up SPF/DKIM and DMARC email authentication for their domains, as was revealed in October 2023.

Google’s new standards state that in order to keep Gmail from rejecting all offensive emails, bulk email senders must also refrain from sending unsolicited communications, offer a one-click unsubscribe option, and reply to unsubscribe requests within two days.

Microsoft suggests specialised services for businesses with high-volume external emailing requirements.

Azure Communication Services (ACS) Email: This pay-as-you-go solution manages large amounts of external messages and is intended for B2C and transactional emails. The documentation for Azure Communication Services contains comprehensive information.

Third-party providers: Legitimate mass commercial email services are provided by a number of specialised third-party companies.

Microsoft also has declared that it will take other, less disruptive measures to stop Exchange Online resources from being misused for malevolent and spammy purposes.