Amazon Connect API /StartOutboundVoiceContact returns 429


I have been using Amazon Connect for several months. We mainly use the StartOutboundVoiceContact endpoint to trigger the Amazon Connect flow via REST request.

But we encountered the error 429 Too Many Request before the month Ends. Based on what I understand, this is because of the service quota allowed in that service. Other endpoints are working fine. but this endpoint is no longer working.

I've already requested to increase the quota and it was already approved. the request is mainly for this endpoint alone.

This endpoint is still not working at this point. I thought it will be refreshed once the request is approved or the next month comes in.

Could anyone give me an idea on how to make this work again?

Thank you in advance

1 Answer
Accepted Answer


You mention that you start StartOutboundVoiceContact via REST request. Is this REST endpoint service by an Amazon API Gateway ?

The reason why I am asking is that 429 code is also delivered by API gtw when too many parallel requests occur: see

So, you may also want to check your quotas for API gtw to make sure that you have enough capacity on that side as well.



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answered 20 days ago
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reviewed 20 days ago
  • Hi,

    The call to StartOutboundVoiceContact is via MuleSoft and Postman. I actually checked API gateway and since I do not use that service, there is nothing in there. And of all the Amazon Connect API endpoint, I am only using one endpoint on this project. So my request to increase the quota was for this endpoint alone.

    I actually test ListUsers endpoint in Amazon connect and it works fine.

    Is there like a separate request for this since I already completed the quota request?

  • Hi Owen, yes, Api Gateway has its own distinct quotas. They are detailled at

    You can also open requests to adjust them to your needs.

  • Hi @Didier_Durand,

    I mean, I do not use API gateway. This is straight-forward to Amazon Connect. Please correct me if my understanding is correct. If Amazon Connect is passing through the API gateway - how would I know if what service quota should I request to be increased?

    What I want to know, once the quota was increased, is the 429 error will be fixed right away? If not, is there a separate request to for it to be refreshed at some point?

    There is also a statement that if the quota was exceeded, Amazon will reject all request until the remainder of the interval. What is this interval and how would I check the interval?

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