Issue with Scheduling Callback via Zoom API

Santhosh1 · April 15, 2026, 1:31pm

Hi Team,

I am attempting to schedule a callback from my Zoom account using the API. I have prior experience working with Zoom APIs and have successfully executed multiple API calls in the past. However, I am currently facing an issue specifically with scheduling a callback.

When I attempt to create a scheduled callback, I receive the following error response:

{
    "code": 300,
    "message": "Invalid value for field 'null': invalid type"
}

Based on the documentation, this error indicates that one of the fields in the request may have an incorrect format or data type. However, I have reviewed my request and believe it follows the required structure.

Please find the request details below:

Endpoint:
https://api.zoom.us/v2/contact_center/queues/ZWQC647829DDA8E5E9235F498C778157CEE/scheduled_callbacks/events

Method: POST
Content-Type: application/json

Request Body:

{
  "start_time": "2026-04-17T15:00:00Z",
  "attendees": [
    {
      "first_name": "Vignesh",
      "last_name": "Chellamani",
      "phone_number": "+916369748867",
      "email": "acvignesh22@gmail.com"
    }
  ]
}

I am using the following Queue ID:
ZWQC647829DDA8E5E9235F498C778157CEE

Below are the details retrieved for this queue:

{
    "queue_id": "ZWQC647829DDA8E5E9235F498C778157CEE",
    "cc_queue_id": "tbb85R2AT6aITy4hIpLwcw",
    "queue_name": "Zoomly Schedule Callback",
    "channel_types": [
        "voice"
    ],
    "channel": "voice",
    "agents_count": 3,
    "supervisors_count": 0,
    "modified_by": "QIdCXmnhREmoPzqlZViALw",
    "last_modified_time": "2025-09-12T08:40:46Z"
}

I have shared all the relevant details above for your reference. Could you please review my API request and confirm whether the request format or parameters are incorrect?

Your assistance in resolving this issue would be greatly appreciated. Please let me know if any additional information is required.

Thank you for your support.

Best regards,
Santhosh

donte.zoom · April 15, 2026, 5:43pm

Thank you for posting, @Santhosh1 ! As a test, can you remove the plus sign (+) from the phone number and share the results? Also, I noticed you entered 12 digits. Is that the correct length for the country associated with that number?

Santhosh1 · April 16, 2026, 4:56am

Hi Dear,

I attempted the API request again after removing the “+” symbol from the request body; however, I am still receiving the same response.

Please find the API details below for your reference:

URL:
https://api.zoom.us/v2/contact_center/queues/ZWQC647829DDA8E5E9235F498C778157CEE/scheduled_callbacks/events

Request Body:

{
  "attendees": [
    {
      "email": "cpbala4@gmail.com",
      "first_name": "Jill",
      "last_name": "Chill",
      "phone_number": "97144986467"
    }
  ],
  "start_time": "2026-04-17T15:00:00Z"
}

Response:

{
  "code": 300,
  "message": "Invalid value for field 'null': invalid type"
}

I suspect the issue might be related to the start_time format in the request body. Could you please confirm if the format I am using is correct?

Additionally, I would appreciate it if you could perform a test API call from your end and share the results. I will replicate the same on my side for comparison.

Looking forward to your guidance.

Santhosh1 · April 16, 2026, 5:16am

Also, I’m passing my UAE mobile number which is correct

Santhosh1 · April 17, 2026, 8:18am

Hi Zoom Team,
Have we received any update on my request? I am following the steps mentioned in the Zoom API documentation; however, my API call is failing with a 300 status code.

I would appreciate your support in resolving this issue.

Santhosh1 · April 20, 2026, 9:12am

Hi Zoom Team,

Requesting your support on the above matter.
@donte.zoom @justin.steinberg

Regards,
Santhosh

justin.steinberg · April 22, 2026, 8:22pm

Hi @Santhosh1 I am checking on this issue for you and will share an update.

Santhosh1 · April 24, 2026, 9:48am

Thanks for the update @justin.steinberg
Waiting for your response

Santhosh1 · April 30, 2026, 5:30am

Hi @justin.steinberg , Did we got any update?

donte.zoom · May 4, 2026, 3:36pm

@Santhosh1 ,

Sorry for the delay—I needed to get an account enabled to properly test this.

I was able to reproduce the behavior as described. I’ve created an internal ticket (ZSEE-202311) for further investigation and will share updates as soon as I have more details. In the meantime, let me know if you uncover anything additional on your end that could help with debugging.

Pranjal.zoom · May 4, 2026, 5:37pm

Hi @Santhosh1 ,

Based on the current Zoom Contact Center API design for scheduling callbacks, your request body is structurally close, but the error “Invalid value for field ‘null’: invalid type” indicates that a required field or data type is missing or not recognized by the endpoint.

Here’s how to correct and validate the call.

Correct Request Format

{
  "attendees": [
    {
      "first_name": "Vignesh",
      "last_name": "Chellamani",
      "email": "XXXXXXXX@gmail.com",
      "phone_number": "+911234567890"
    }
  ],
  "start_time": "2026-04-17T15:00:00Z",
  "time_zone": "Asia/Kolkata",
  "language": "en-US",
  "callback_type": "voice",
  "source": "api",
  "notes": "Customer requested call between 3 PM–4 PM IST"
}

Endpoint:

POST https://api.zoom.us/v2/contact_center/queues/ZWQC647829DDA8E5E9235F498C778157CEE/scheduled_callbacks/events

Santhosh1 · May 5, 2026, 4:36am

Hi @Pranjal.zoom

Thank you for your response on this matter.

We have tried using the exact request format you shared. Please find the details below:

Request Body:

{  
  "attendees": [    
    {      
      "first_name": "Vignesh",      
      "last_name": "Chellamani",      
      "email": "acvignesh22@gmail.com",      
      "phone_number": "+911234567890"    
    }  
  ],  
  "start_time": "2026-05-17T15:00:00Z",  
  "time_zone": "Asia/Kolkata",  
  "language": "en-US",  
  "callback_type": "voice",  
  "source": "api",  
  "notes": "Customer requested call between 3 PM–4 PM IST"
}

Endpoint:

https://api.zoom.us/v2/contact_center/queues/ZWQC647829DDA8E5E9235F498C778157CEE/scheduled_callbacks/events

However, we are still encountering the same error:

"code": 300,
"message": "Invalid value for field 'null': invalid type"

Could you please confirm if there are any account-level settings that need to be enabled specifically for this API to function correctly? We have already reviewed the configuration on our end, and everything appears to be in order.

Additionally, as Justin previously mentioned, could you please check if there might be any issue or bug associated with our account?

We would appreciate your assistance in identifying the root cause and resolving this issue at the earliest.

Looking forward to your response.

Santhosh1 · May 5, 2026, 4:37am

@Pranjal.zoom Attached Screenshot for your reference

Santhosh1 · May 7, 2026, 4:51pm

Dear Team, @donte.zoom @Pranjal.zoom @justin.steinberg

We have been facing this issue for the past two weeks, and it is significantly affecting our business operations. Despite following the troubleshooting steps provided by your team, the API continues to fail.

Could you please investigate this issue on priority and provide us with an update at the earliest?

Thank you for your support.

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Issue with Scheduling Callback via Zoom API

Correct Request Format

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