Azure DevOps - How to Publish Artifacts Using REST API in Python?

Try below with logging which help to diagnose the issue:

import os
import requests
import logging

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

organization = 'your_organization'
project = 'your_project'
build_id = 'your_build_id'
artifact_name = 'your_artifact_name'
artifact_files = ['path/to/your/artifact1', 'path/to/your/artifact2']
container_url = f"https://dev.azure.com/{organization}/{project}/_apis/resources/Containers/c82916f3-4665-43bf-8927-e05a3b6492a9"

# Part 1 - Create artifact metadata
url = f"https://dev.azure.com/{organization}/{project}/_apis/build/builds/{build_id}/artifacts?artifactName={artifact_name}&api-version=7.1-preview.5"
headers = {
    "Authorization": f"Basic {ACCESS_TOKEN}",
    "Accept": "application/json",
    "Content-Type": "application/json",
}
payload = {
    "name": artifact_name,
    "resource": {
        "type": "Container",
        "data": artifact_name,
        "properties": {
            "RootId": artifact_name
        }
    },
}
logger.info("Creating artifact metadata...")
response = requests.post(url, headers=headers, json=payload)
if response.status_code == 200:
    logger.info("Artifact metadata created successfully.")
    response_json = response.json()
    logger.info(f"Create Pre-Payload Response: {response_json}")
else:
    logger.error(f"Failed to create artifact metadata: {response.status_code}, {response.text}")

# Part 2 - Upload artifacts
headers = {
    "Authorization": f"Basic {ACCESS_TOKEN}",
    "Content-Type": "application/octet-stream",
}
for artifact_file in artifact_files:
    if not os.path.exists(artifact_file):
        logger.warning(f"File {artifact_file} does not exist. Skipping.")
        continue
    item_path = f"{artifact_name}/{os.path.basename(artifact_file)}"
    upload_url = f"{container_url}?itemPath={item_path}"
    logger.info(f"Uploading: {artifact_file} to {upload_url}")
    with open(artifact_file, "rb") as f:
        response = requests.put(upload_url, headers=headers, data=f)
        if response.status_code == 201:
            logger.info(f"File {artifact_file} uploaded successfully.")
        else:
            logger.error(f"Failed to upload {artifact_file}: {response.status_code}, {response.text}")