###########################################
# Apache lines for flask app
Listen 8081
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_http_module modules/mod_proxy_http.so

<VirtualHost *:8081>
    ServerName acsserver
    DocumentRoot "C:/Apache24/htdocs/flask_demo"  
    #Replace with the actual path to your app directory
    ProxyPass /flaskapp http://127.0.0.1:8871/
    ProxyPassReverse /flaskapp http://127.0.0.1:8871/
</VirtualHost>
 
###########################################


Apache is listening at 8081
Waitress is listening at 8871

Virtualhost section in httpd.conf file manages communication from Apache to waitress


Start waitress_server.py file in virtual environment
Start Apache 
Then Access url from client pc
http://203.82.57.244:8081/flaskapp