If during the testing of the SQL database connection an error popup will shown that the "adaptive Server connection failed" you have selected the wrong database type. Like you might have setup a MySQL server and selected MS SQL. 

Change this and retest the connection.

[S1000][UnixODBC][FreeTDS][SQL Server] Unable to connect to data source 

[S1000][UnixODBC][FreeTDS][SQL Server] Adaptive Server Connection Failed

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