Sending SMS is not available

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  • Problem
  • Updated 6 months ago
We started sending SMS to our opt-in clients today, and after sending about 5,000 or so messages, we are receiving the following error:

"Sending SMS from/to extension numbers is not available"

What is the issue?

Posted 6 months ago

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Tyler Long, Official Rep

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Are you still experiencing this issue?

I know there is a quota limit. You are not allowed to send too many SMS in a short time. I am not sure if it is the issue you encountered.
What are the limits for SMS?  I could not find anything in the API documentation regarding limits within a specific period of time.  Can I contact support to request an increase if the quota limits are not sufficient?
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Phong Vu, Devangelist

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There are 2 separate limitations on sending SMS:

1. API rate limit: as you can see the SMS API group is Medium and that means that you can call the API 40 times per minute. (

2. FCC limit on long code SMS

"In addition to the API rate limit, phone number use is governed by the FCC. Currently, RingCentral provides local phone numbers, aka long codes, for SMS and are typically used for non-marketing person-to-person and small-group text use cases. Based on our experience, we recommend sending up to 500 SMS text per long code per day. If you wish to send more than this, contact us our support team to discuss your use case."

Please double check and avoid hitting the limit.

If it is the API rate limit, simply implement some delay to send max 40 msg / minute
If it is the FCC limit, you can go around the limit by using several numbers from different extensions to send the message.

Hope this helps,

+ Phong