I built an Rshiny application that pulls data from Microsoft Azure. My application works locally when I use the 'SQL Server' driver in my connection string, but does not work when I publish the app on shinyapps.io. 
Based on a suggestion from [here](https://itsalocke.com/blog/connecting-to-sql-server-on-shinyapps.io/), I have been trying to use the 'FreeTDS' driver to connect with Azure when publishing on shinyapps.io but I am not having any luck. 

Here is my connection string:

```
con <- dbConnect(odbc::odbc(),
                 Driver = "FreeTDS",
                 Server = "servername", 
                 Database = "databasename",
                 Uid = "uid",
                 Pwd = "pwd",
                 Port = 1433,
                 TDS_Version = 9.0)

```

I receive the following error message when using the 'FreeTDS' driver: 

```
Error in value[[3L]](cond) : 
  nanodbc/nanodbc.cpp:950: 08001: [unixODBC][FreeTDS][SQL Server]Unable to connect to data source 

```

I have tried using TDS\_Version 7.0, 7.2, 7.4, 9.0 - none have worked. Can anyone help me decode this error message? Thank you!

Note: I am working with R 3.6 on Windows 10. I have whitelisted shinyapps.io IP addresses on Azure, so that is not the issue.