Can you login as sa?

>>>>>Hi,
>>>>>
>>>>>I am testing access to a new customer database (not the first time a very similar environment). What happens is when I use Windows authentication (specify in the connection string IntegratedSecurity True) connection works. But when I try SQL Server authentication I get connection error (basically connection denied). For SQL Server authentication I created login and then in the database I created user of the same name. The user has roles: db_datareader, db_datawriter, db_owner. But nothing works. I have double checked the password (I made it very simple 'test') but can't make the SQL Server authentication to work.
>>>>>What could be missing? TIA.
>>>>
>>>>Could you connect with SSMS using this login?
>>>
>>>No. I get error "Cannot connect to SERVERNAME" What could it tell me? Thank you
>>
>>Connect with SSMS using Windows authentication. Right click on this login and "Properties->Status"
>>Also make sure that this login has rights on master DB.
>
>No problems there. The Status is Grant permission to connect to database engine and Enabled Login. The login also has rights on master DB. I even created a second login and user, very simple, both name and password are 'test' and still no luck.
>Anything else I can try?