I have built a web service that is to be hosted on IIS which is to connect to a MySql database that i am hosting on Winhost. It connects and functions fine from my local environment, but when i publish my service and try to invoke a web method i get the following error message: System.IO.FileNotFoundException: Could not load file or assembly 'MySql.Data, Version=18.104.22.168, Culture=neutral, PublicKeyToken=c5687fc88969c44d' or one of its dependencies. The system cannot find the file specified. at WebService2.Service1.CheckUsername(String username) I am not sure how to go about fixing this. Any help would be greatly appreciated.