I am getting this error while installing WordPress using Windows platform installer 5.0 on a Windows Server 2012R2.
Currently I have a php site with mySQL on that server which is running fine, PHP, MYSQL was already installed as part of setting up that site couple of months ago.
MySQL .NET Connector was already installed, I have repair it(http://dancerscode.com/blog/the-annoying-mysql-web-platform-installer-bug/) using latest installer as well. Installed WebMatrix3 which was mentioned in same article but No luck.
I have made sure that mySQL password is correct by logging in using command line.