Error: "Specified SQL Server not found" when connecting SQL Server to R Markdown

Question

I'm getting this error when trying to connect my SQL Server to R Markdown

Error: nanodbc/nanodbc.cpp:1138: 01S00
[Microsoft][ODBC SQL Server Driver][DBNETLIB]Specified SQL server not found. 
[Microsoft][ODBC SQL Server Driver][DBNETLIB]ConnectionOpen (Connect()). 
[Microsoft][ODBC SQL Server Driver]Invalid connection string attribute

This is my connection code

{r Connection to SQL Database,echo=T, warning=F, message=F, eval=T}
con <- DBI::dbConnect(odbc(),
                      Driver = "SQL Server",
                      Server = "MY-PC/SQLEXPRESS",
                      Database = "Cyclistic",
                      Port = 8524)

I have no experience in these types of things, I only want to show my SQL queries in the markdown.

If there's some other way that I could do this please tell me, or if I'm missing something obvious.