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Email service providers impose IP block on Salesforce outbound email IP addresses

Julkaisupäivä: May 4, 2026
Kuvaus

Behavior:
Outbound emails from Salesforce may bounce when sending to some Email Service Providers (ESP). An ESP is a service such as Microsoft (Office 365/Exchange Online), Yahoo Mail, Google Mail (Gmail), or AOL that receives and delivers email on behalf of its users. The bounce message may vary; however, the failure reason typically indicates that a specific IP address has been blocked.

Cause:
Large ESPs such as Microsoft, Yahoo, Google Mail, and AOL can potentially impose an inbound IP Block or Throttle for specific Salesforce IP addresses. This causes emails from some Salesforce organizations to temporarily or permanently bounce.
The behaviour can stem from two sources:

  • New IP reputation: A newly introduced Salesforce IP address may not yet have an established reputation, causing ESPs to treat it with caution.
  • High volume emails: A large influx of emails from a Salesforce organization to many recipients on the same domain can trigger spam or abuse detection on the recipient server.

In most cases when the issue occurs, the block is limited to a small subset of IP addresses.

Note: This article refers to Email Service Providers (ESP) and not blocklist providers, of which there are many. For Salesforce's policy regarding blocklist providers, refer to SPAM Blackhole Lists: How Salesforce Email Delivery is Affected.

Ratkaisu

This article explains the steps to take when Salesforce outbound email is blocked or throttled by an Email Service Provider (ESP). Follow the actions below to remediate the issue and prevent recurrence.

Immediate Actions

  • Check your email logs to determine if emails from Salesforce to your domain are being throttled or blocked. If you suspect an ESP such as Microsoft or Google is involved, contact your ESP directly — algorithm, tenant, or policy changes on their side may be the root cause and they can assist.
  • If you are using Microsoft as your ESP and this issue is affecting delivery to your own domain, use the Microsoft support form to address the issue. Working directly with the blocker is often the quickest remediation path.
  • Log a Salesforce Support Case if this issue is affecting your Salesforce organization.

How Salesforce Responds

  • The Salesforce technology team routinely works with large ESPs to ensure the highest levels of email deliverability.
  • When the Salesforce technical team detects or is notified of a block or throttle, they will expedite coordination with the ESP to remove the restriction.
  • Salesforce will actively pursue a resolution with the third-party ESP and push for a timely resolution until restrictions have been lifted.
  • Salesforce will determine the root cause of the throttle or block to ensure the issue is not recurring, and will work to prevent further adverse action by the ESP.

Preventive Measures

  • To avoid potential ESP throttling, use Email Relay. Email Relay allows organizations to route Salesforce outbound email through their own mail servers, giving them control over their own email deliverability and sourcing mail from their own IP addresses.
  • See also: Considerations for Setting Up Email Relay
Knowledge-artikkelin numero

000381883

 
Ladataan
Salesforce Help | Article