SQL authentication might not be enabled by default in SQL Server

Recently I needed to get a third-party application connected to an SQL Server database. The application uses an SQL Server account rather than integrated Windows authentication. Even though I was very certain I had created the account correctly, the application reported that logon failed. Looking through the SQL Server event logs, I found the explanation: logging in with database accounts was not enabled. (That seems to be the default configuration? I'm not sure why.) Such logons can be enabled in the security section of the server properties in SSMS.