Possible Reasons:
Web Server not running
URL incorrect
Project not published
Web server hosting wrong folder
Solution:
Verify Web Server is running and hosting the correct folder
Make certain project is published
Verify URL
If above is not the reason, you need to verify that Web Client configuration is done properly.
You can refer below Video:
https://www.youtube.com/watch?v=mc07e9gZag0
Web Server not running
URL incorrect
Project not published
Web server hosting wrong folder
Solution:
Verify Web Server is running and hosting the correct folder
Make certain project is published
Verify URL
If above is not the reason, you need to verify that Web Client configuration is done properly.
You can refer below Video:
https://www.youtube.com/watch?v=mc07e9gZag0