FBA - machine.config modification issue

I am trying to implement form based authentication in my SharePoint 2013 Env.  As a first step to implementing FBA, we need to modify the machine.config file in the server.

I started by just adding the below statement in the machine.config file, with server being replaced by my server name. Even before going to next step, I tried to check my sharepoint site , but is not working now and it throws HTTP 503 Unavailable error, with my application pool failing to restart. What am I doing wrong here?

In the <ConnectionString> section, add the following line:
< add connectionString=”Server=<SERVER>;Database=aspnetdb;Integrated Security=true” name=”FBADB” />