Issue with POST request creating Calls in CRM

Issue with POST request creating Calls in CRM

Hello,

I am in the middle of integrating some 3rd party Call center API with Zoho CRM and going through our logs I see some discrepencies. 

We sometimes get an error:
  1. {"data":[{"code":"INVALID_DATA","details":{"api_name":"Call_Duration","json_path":"$.data[0].Call_Duration"},"message":"Please provide a valid call start time and duration","status":"error"}]},"extra":[]}}

The post request looks like so:
  1. {
      "Subject": "Outbound call to X",
      "Call_Type": "Outbound",
      "Call_Status": "Completed",
      "Call_Start_Time": "2025-06-18T10:26:20+00:00",
      "Call_Duration": "00:24",
      "Who_Id": { "name": "X", "id": "X" },
      "Owner": { "name": "X", "id": "X" },
      "$se_module": "Accounts",
      "What_Id": { "name": "X", "id": "X" }
    }
The issue is that the data is formatted correctly, so when I run this POST request manually with the exact same data it will succeed. My backend formats the start time to ISO8601 and duration is always sent as "i:s"(granted the documentation specified H:i, but this seems like an oversight?) - example if a call lasts 20 seconds it would send "00:20". 

The issue happens randomly and is not consistent, my work around has been that I simply retry the POST call Y amount of times and it will usually post succesfully - however this does not seem like a healthy work around and I would rather find a correct solution to the issue. 

My initial thought was that I was hitting some sort of API limit and that the error message is wrong. But as I read Zoho does not have an API limit per say, but use a concurrency limit - would this be the issue in this case and what would the work around be?

Any help would be greatly appreciated.