"Failed to connect to database: Error: Can't connect to MySQL server on 'srv-sql2008' (0)" between R and MySQL server

Question

I need to connect the sql server databases to R. I tried many times and I search I find many methods here Connect R to a SQL Server database engine. But It doesn't work

So I search more and I find this one https://mkmanu.wordpress.com/2014/07/24/r-and-mysql-a-tutorial-for-beginners/

I just follow the first step:

library(RMySQL)

mydb = dbConnect(MySQL(), user='manoj', password='password', host='localhost')

But this error was shown:

Failed to connect to database: Error: Can't connect to MySQL server on 'srv-sql2008' (0)

How can I resolve this please?