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ACS Email Quota Increase — kairos-nonprod-app-comms returning 429 on all sends

Alex Maramaldo 0 Reputation points
2026-06-03T18:56:10.6533333+00:00

Customer Information

  • Company name: Kairos
  • Company website: kairosinflow.com
  • Provide a brief description of your business: Kairos is a manufacturing control layer — intelligence that makes MRP, ERP, and APS systems work better together. It sits above existing manufacturing tools, understands their collective

state, and actively controls when and how they are used, including production scheduling, schedule change management, and ERP writeback.

Email Service Information

  • Subscription ID: b5bb0a93-5979-4501-9867-63632b580434
  • Azure Communication Services Resource Name: kairos-nonprod-app-comms
  • Is your custom domain already set up and currently used for sending messages: No — using Azure-managed domain
  • Indicate the domain from which you are currently sending emails: 750f37b7-2c41-4661-8725-0ccd3bb05123.azurecomm.net

Usage Information

  1. What type of emails do you send? Transactional — automated approval request and decision notifications sent to internal employees when a Schedule Change Request (SCR) is submitted or actioned in the production scheduling system.
  2. Specify the expected volume:
  • Max rate per minute: 10 messages/minute
  • Max rate per hour: 60 messages/hour
  • Max rate per day: 300 messages/day

Additional Information

Source of email addresses: All recipients are internal employees whose email addresses are stored in the application's user database. Addresses are provisioned by system administrators and are never acquired from external lists or marketing sources.

How do you manage unsubscribes and bouncebacks: These are transactional system notifications sent exclusively to internal employees who are designated approvers in the production scheduling workflow. There is no opt-in/opt-out mechanism as delivery is a business requirement of the role. Bouncebacks are logged in the application's email_notifications audit table; an administrator can update or deactivate a user's account to stop future notifications. No bulk mailing or marketing emails are sent through this resource.

Azure Communication Services

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  1. Amira Bedhiafi 42,046 Reputation points MVP Volunteer Moderator
    2026-06-03T19:27:18.79+00:00

    Hello Alex !

    Thank you for posting on MS Learn Q&A.

    The main issue is that they are using an Azure-managed domain an not a verified custom domain. ACS Email managed domains have very low limits: 5 emails/minute and 10 emails/hour and higher limits are not available for managed domains and quota increases are only available for verified custom domains not Azure-managed domains.

    https://learn.microsoft.com/en-us/azure/communication-services/concepts/service-limits

    ACS returns 429 Too Many Requests when the per minute or per hour sending tier is reached and retry should respect throttling and not keep sending in a tight loop.

    https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/email/send-email-advanced/throw-exception-when-tier-limit-reached

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