Are you trying to upload csv from local mochine?
                
     
                                    
            Yes, from a local machine 
                
     
                                    
            I got that working using below Python code.
Upload API:
import requests
import json
url = 'https://fra1.qualtrics.com/API/v3/surveys/SV_XXXX/import-responses'
headers = {
    'Content-Type': 'text/csv',
    'charset': 'UTF-8',
    'X-API-TOKEN': 'XXXX'
}
with open('upload.csv', 'rb') as file:
    response = requests.post(url, headers=headers, data=file)
print(response.text)
Progress API
import requests
url = "https://fra1.qualtrics.com/API/v3/surveys/SV_XXXX/import-responses/<Progress ID>"
headers = {
    "Content-Type": "application/json",
    "X-API-TOKEN": "XXXX"
}
response = requests.request("GET", url, headers=headers)
print(response.text)
Make sure to use correct datacenter id as this API won’t work in proxy request. We can also combine both the code and check the progress at a fixed interval.