使用Microsoft Graph API从SharePoint加载文件至Databricks时的授权错误排查求助

大家好，我现在尝试通过Microsoft应用注册和Microsoft Graph API从SharePoint加载文件到Databricks，但一直遇到授权错误。我不确定是缺少必要权限，还是文件路径设置有问题。目前我的应用已经配置了Sites.Read.All和Sites.Select权限，有没有大佬能帮我看看问题出在哪？

我的代码如下：

sharepoint_site = "company_name.sharepoint.com/sites/site_name"
sharepoint_file_path = "relative_path/file.xlsx"
client_id = dbutils.secrets.get("secret_scope", "client_id")
tenant_id = dbutils.secrets.get("secret_scope", "tenant_id")
client_secret = dbutils.secrets.get("secret_scope", "client_secret")

auth_url = f"https://login.microsoftonline.com/{tenant_id}/oauth2/v2.0/token"
auth_data = {
    "grant_type": "client_credentials",
    "client_id": client_id,
    "client_secret": client_secret,
    "scope": "https://graph.microsoft.com/.default"
}

auth_response = requests.post(auth_url, data=auth_data)
if auth_response.status_code != 200:
    print("Fehler bei der Authentifizierung")
    print(auth_response.text)
    exit()

access_token = auth_response.json().get("access_token")

headers = {"Authorization": f"Bearer {access_token}"}
download_url = f"https://graph.microsoft.com/v1.0/sites/{sharepoint_site}/drive/root:/{sharepoint_file_path}:/content"
file_response = requests.get(download_url, headers=headers)
if file_response.status_code == 200:
    file_path = "/dbfs/path.xlsx"
    with open(file_path, "wb") as f:
        f.write(file_response.content)
    print("Datei heruntergeladen!")
else:
    print(f"Fehler: {file_response.status_code}")
    print(file_response.text)

目前我能成功获取到access_token，但请求文件时返回授权相关错误，实在搞不清是权限配置的问题，还是文件路径的写法不对，麻烦帮忙排查下可能的原因，谢谢！

备注：内容来源于stack exchange，提问作者yannik0103