Getting error 4429 on Text to Speech even though I have not exceeded the free 500K characters per month

Question

Getting error 4429 on Text to Speech even though I have not exceeded the free 500K characters per month

April 35

I'm trying to use the Free tier of the Azure Text to Speech API, but I'm running into error 4429:

The request is throttled because you have exceeded the concurrent request limit allowed for your sub websocket error code: 4429

This is weird because I have exceeded neither the 500K/mo. free characters limit or the 20 transactions per 60 seconds limit. I can see in my Metrics tab that I've only used ~65K characters since August 1, 12:00 AM UTC*, and it can't be the other limit because I've waited a few minutes and I'm still getting the error as soon as I try to use TTS.

*I contacted Sales through live chat, and was told the following:

The monthly limit refreshes at the beginning of each calendar month, based on the UTC time zone. For example, if you use 300,000 characters in January, you will have 200,000 characters left for the rest of January.

Maybe there's some other limit I don't know about? I've looked everywhere though and as far as I can tell the only limits are 500K char/mo. and 20 transactions/minute.

VasaviLankipalle-MSFT 18,576 Reputation points

2023-08-09T01:58:04.3533333+00:00

Hello @April , Thanks for using Microsoft Q&A Platform.

The concurrent request limit error refers to the maximum number of requests that can be processed simultaneously by the Text to Speech API.

Have you tried reducing the number of requests? You can also try spreading out your requests over a longer period of time as mentioned here: https://learn.microsoft.com/en-us/azure/ai-services/speech-service/speech-services-quotas-and-limits#text-to-speech-increase-concurrent-request-limit

If you are still experiencing the issue, maybe you can try upgrading your subscription to a higher tier that allows for more concurrent requests.
April 35 Reputation points

2023-08-09T08:42:50.6033333+00:00

@VasaviLankipalle-MSFT As I said, that's not the issue — I am only doing one request at a time, and I am absolutely sure I'm not hitting the ratelimit of 20 requests per minute, because I just tried it now and got the error after doing only three requests total today.
April 35 Reputation points

2023-08-09T11:03:57.82+00:00

Honestly, this whole situation is not giving me confidence in Azure. If a free trial is meant to convince me to pay for a service, I must say it's not doing a good job at that. I need something reliable — I can't have a service that will just randomly start denying me, with no easy way to find out why, and with no way to contact anyone that can tell me what's going wrong.
EHLA 5 Reputation points

2024-02-07T02:32:10.9766667+00:00

I am having the same issue. I start my work today. I manually call the api for once, it works fine. After I get my result, I call the api again and it gives me 4429 error.
I wait for let say one minute and it works again, but fail the next call again. This is the first four calls I do today. And the api didn't open for others to use.

the string I pass is only one single word. the limit I use is still less than 5%.
I don't mind if I update to a paid tier, but what I concern is that if there is hidden limitation that I don't know.

It works fine a few day ago, but this week it starts to fail. I don't know why.

Your answer

VasaviLankipalle-MSFT 18,576 Reputation points

2023-08-09T01:58:04.3533333+00:00

Hello @April , Thanks for using Microsoft Q&A Platform.

The concurrent request limit error refers to the maximum number of requests that can be processed simultaneously by the Text to Speech API.

Have you tried reducing the number of requests? You can also try spreading out your requests over a longer period of time as mentioned here: https://learn.microsoft.com/en-us/azure/ai-services/speech-service/speech-services-quotas-and-limits#text-to-speech-increase-concurrent-request-limit

If you are still experiencing the issue, maybe you can try upgrading your subscription to a higher tier that allows for more concurrent requests.
April 35 Reputation points

2023-08-09T08:42:50.6033333+00:00

@VasaviLankipalle-MSFT As I said, that's not the issue — I am only doing one request at a time, and I am absolutely sure I'm not hitting the ratelimit of 20 requests per minute, because I just tried it now and got the error after doing only three requests total today.
April 35 Reputation points

2023-08-09T11:03:57.82+00:00

Honestly, this whole situation is not giving me confidence in Azure. If a free trial is meant to convince me to pay for a service, I must say it's not doing a good job at that. I need something reliable — I can't have a service that will just randomly start denying me, with no easy way to find out why, and with no way to contact anyone that can tell me what's going wrong.
EHLA 5 Reputation points

2024-02-07T02:32:10.9766667+00:00

I am having the same issue. I start my work today. I manually call the api for once, it works fine. After I get my result, I call the api again and it gives me 4429 error.
I wait for let say one minute and it works again, but fail the next call again. This is the first four calls I do today. And the api didn't open for others to use.

the string I pass is only one single word. the limit I use is still less than 5%.
I don't mind if I update to a paid tier, but what I concern is that if there is hidden limitation that I don't know.

It works fine a few day ago, but this week it starts to fail. I don't know why.

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Getting error 4429 on Text to Speech even though I have not exceeded the free 500K characters per month

Your answer