Faccing issue while exporting csv file in django

I am exporting a CSV file on the frontend as the user clicks on the download button, but sometimes I get an empty file and sometimes I get the exact file that I want. This is happening only on the deployment of the app.

The function which is doing all this is :(the channel_list contains a list of dictionaries which has 'url' as key)

def exportfile(request):    response = HttpResponse(content_type='text/csv')    response['Content-Disposition'] = 'attachement; filename="channelUrls.csv"'    writer = csv.writer(response)    for list in channel_list:        writer.writerow([list['url']])    channel_list.clear()    return response

The function which is inserting data to channel_list is :

channel_list = []def home(request):    context = {'message' : ""}    if request.method == 'POST':        rows = []        video_id = []        file = request.FILES["file"].readlines()        for f in file:            rows.append((f.decode('utf-8')))        for row in rows[0:len(rows)-1]:             video_id.append((row[-13:]))        video_id.append((rows[len(rows)-1][-11:]))        video_id = [x.replace("\r\n","") for x in video_id]        search_url = 'https://www.googleapis.com/youtube/v3/videos'        parameter = {'key' : settings.YOUTUBE_DATA_API_KEY,'part' : 'snippet','id' : ','.join(video_id)        }        data = requests.get(search_url,params=parameter)        results = data.json()['items']        temp_list = []        for result in results:            data = {'name' : result['snippet']['channelTitle'],'url' :  f'https://www.youtube.com/channel/{ result["snippet"]["channelId"] }'            }            temp_list.append(data)        [channel_list.append(x) for x in temp_list if x not in channel_list]        context['message'] = "Click on Download File to download the file"    return render(request,'index.html',context)

Complete code of views.py file :

from urllib import responsefrom django.shortcuts import render,HttpResponsefrom django.conf import settingsimport requestsimport csvchannel_list = []def home(request):    context = {'message' : ""}    if request.method == 'POST':        rows = []        video_id = []        file = request.FILES["file"].readlines()        for f in file:            rows.append((f.decode('utf-8')))        for row in rows[0:len(rows)-1]:             video_id.append((row[-13:]))        video_id.append((rows[len(rows)-1][-11:]))        video_id = [x.replace("\r\n","") for x in video_id]        search_url = 'https://www.googleapis.com/youtube/v3/videos'        parameter = {'key' : settings.YOUTUBE_DATA_API_KEY,'part' : 'snippet','id' : ','.join(video_id)        }        data = requests.get(search_url,params=parameter)        results = data.json()['items']        temp_list = []        for result in results:            data = {'name' : result['snippet']['channelTitle'],'url' :  f'https://www.youtube.com/channel/{ result["snippet"]["channelId"] }'            }            temp_list.append(data)        [channel_list.append(x) for x in temp_list if x not in channel_list]        context['message'] = "Click on Download File to download the file"    return render(request,'index.html',context)def exportfile(request):    response = HttpResponse(content_type='text/csv')    response['Content-Disposition'] = 'attachement; filename="channelUrls.csv"'    writer = csv.writer(response)    for list in channel_list:        writer.writerow([list['url']])    channel_list.clear()    return response