Collection runner returns empty body on 3rd request within collection. Manually send request posses no issues

I made the following collection,
GET with a test script for retrieving a uid value as an variable and a top 1 parameter,
POST with a variable that contains the uid value.

Sending the requests manually posses no issues, even if I run them several times after each other in sequence.

But when I use Run collection to run both requests in sequence in 20 iterations with an 1 second delay between requests. All requests from 3rd iteration on fail.

The message after the 2nd request is always the same,
400 Bad Request
JSONError: No data, empty input at 1:1

As a test I created a Run collection with just 1x simple GET request without any parameter or test script, and run it in 20 iterations and 1 second delay between requests. Again all requests from 3rd iteration on fail.

I did another test by Running the same collection but in Newman which gave me the same failure results.

Authorization type: NTLM

What can I do to run the entire Run collection?

Hi @Phyxius !

Sorry to hear about the issues you’re facing here. Let’s see if we can get this working :slight_smile:

  1. NTLM Authorization: NTLM is a challenge-response authentication protocol, and handling this in rapid consecutive requests (even with a 1-second delay) might be causing an issue. Here’s what you can try:
  • Increase the delay between requests in the Collection Runner. This can help ensure the NTLM handshake completes successfully for each request.
  • Check if any other tools or middleware that handle the NTLM authentication might be rate-limiting or blocking rapid consecutive requests.
  1. Variables Persistence:
  • Ensure that the variable (like uid) you are setting in your first request’s test script is being set correctly in each iteration. An error here could lead to the next request using an incorrect or empty value, causing a 400 Bad Request.
  • Use console.log(pm.variables.get("uid")); to log the uid variable’s value during each iteration to verify it’s being set correctly.
  1. Server Limitations:
  • The server you are interacting with might have some rate limits or connection restrictions in place. Check with your backend team or server logs to see if there’s any limitation applied after a certain number of requests in a short period.
  1. Newman and Collection Runner:
  • Ensure you are using the latest version of Newman and Postman. Outdated versions might have bugs or compatibility issues.
  1. Postman Console:
  • Open the Postman Console (View -> Show Postman Console) before running the collection. This will provide detailed logs for each request and might give more insight into what’s going wrong.
  1. Environment Variables:
  • Ensure that the environment you’re using in the Collection Runner is the same as the one you use while sending requests manually. Any difference in variable values might affect the request behavior.
  1. Proxy and Network Issues:
  • It’s worth checking if there’s a network proxy or firewall that might be interrupting the requests after a certain number.

If none of the above solutions help, please provide more detailed logs or errors you see, especially from the Postman Console. It might give us more context to understand the root cause.

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