C# Databank Server - HTTP/1.0 404 not found Connection: close

I would like another set of eyes as I could not figure out why this error keeps popping out (404 not found).
I wanted to start a data server programmed in C# and display the content of the SQL data table. Once I run the server and HTTP Client it only gave me HTTP/1.0 404 not found Connection: close, <Response body is empty> I tried to set the Port address to 3306 where my SQL data bank is located but no avail.

Could anyone provide me some clues to fix it myself? My current code is as follows: