API call throws exception on bad request

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Posted on by BZF_SA

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Hi,

I am consuming an API to send some data to an external entity. I get a 400 Bad request error and my code jumps to an exception directly and I have no idea what's wrong with the request. I sent the same request through Postman I got an error message in the response. How can get the same results as Postman in my X++ code?

Here is the sample of code that I am using to call the API.

System.Net.HttpWebRequest request;System.IO.Stream stream;System.Exception sysEx;request = System.Net.WebRequest::Create('URL') as System.Net.HttpWebRequest;request.Method = 'POST';request.ContentType = 'application/json';System.Net.WebHeaderCollection headerCollection = request.Headers;headerCollection.Set('Name', 'Value');var utf8 = System.Text.Encoding::get_UTF8();var byteArrayPayload = utf8.GetBytes('{key1:value1,key2:value2}');try        {using (System.IO.Stream dataStream = request.GetRequestStream()){dataStream.Write(byteArrayPayload, 0, byteArrayPayload.Length);}using (System.Net.HttpWebResponse response = request.GetResponse() as System.Net.HttpWebResponse){stream = response.GetResponseStream();System.IO.StreamReader reader = new System.IO.StreamReader(stream);str responseBody = reader.ReadToEnd();}}catch(sysEx){throw;}

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Judy Microsoft Employee on at

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Hi,

What the error messages you got when you sent the request through postman.

The HTTP 400 Bad Request error occurs when the request query parameter or request body content is invalid.

Could you please check the response body to find out which part of the request is not valid.

Best Regards,

Judy

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BZF_SA 179 on at

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I get a proper response that the data is invalid from postman with status code 400 bad request. Thats the same I want to do in X++ to maintain a log.

If the data is valid it works fine.

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Layan Jwei 8,165 Super User 2026 Season 1 on at

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Hi Shahzaib,

It's because you are throwing nothing in the catch.

Try this

System.Exception ex;

try

{

//Logic

}

catch(ex)

{

error(ex.Message);

}

Thanks,

Layan Jweihan

Please mark this answer as "Verified" if it solved your issue. In order to help others who will face a similar issue in the future

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BZF_SA 179 on at

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I have tried to throw ex.message as well but its the same. All I want to achive is to get the response Json and Parse it to create a log.

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Anthony Blake 3,092 Super User 2026 Season 1 on at

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If you can catch a System.Net.WebException, you should have access to the response body, which is what you see in postman.

https://learn.microsoft.com/en-us/dotnet/api/system.net.webexception?view=net-8.0&redirectedfrom=MSDN

This is how to do it in C#, it should be transferrable to X++:

https://stackoverflow.com/questions/7261986/how-to-get-error-information-when-httpwebrequest-getresponse-fails

System.Net.WebException ex;
try
{
// call the API
}
catch(ex)
{
// read the response stream as you do on success, but from from ex.Response.GetResponseStream()
}

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Layan Jwei 8,165 Super User 2026 Season 1 on at

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Hi Shahzaib,

Can you please re-share your code in a proper format?

Also did you debug and see at which line of code does it fail? And when it goes to the catch did you see in the debugger watch what ex is returning?

ex.Message should return the error. Also did you try after the catch to put info(responseBody) and check if the result of postman appears?

Thanks,

Layan Jweihan

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BZF_SA 179 on at

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System.Net.HttpWebRequest request; System.IO.Stream stream; System.Exception sysEx; request = System.Net.WebRequest::Create('URL') as System.Net.HttpWebRequest; request.Method = 'POST'; request.ContentType = 'application/json'; System.Net.WebHeaderCollection headerCollection = request.Headers; headerCollection.Set('Name', 'Value'); var utf8 = System.Text.Encoding::get_UTF8(); var byteArrayPayload = utf8.GetBytes('{key1:value1,key2:value2}'); try { using (System.IO.Stream dataStream = request.GetRequestStream()) { dataStream.Write(byteArrayPayload, 0, byteArrayPayload.Length); } using (System.Net.HttpWebResponse response = request.GetResponse() as System.Net.HttpWebResponse) { stream = response.GetResponseStream(); System.IO.StreamReader reader = new System.IO.StreamReader(stream); str responseBody = reader.ReadToEnd(); } } catch(sysEx) { throw; }

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BZF_SA 179 on at

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Thank You, Anthony Blake.

your solution worked for me.

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Anthony Blake 3,092 Super User 2026 Season 1 on at

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Excellent news!

Please mark my solution as verified to help future users/google searchers find their solution

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