sql server authentication login failed

I have SQL Server 2014 on my Windows Server 2012 R2. I can connect locally to SQL Server from Management Studio using Windows Authentication.

I decided to switch to SQL Server Authentication (because I need access from other computer). I created new Login using Management Studio, but get error: Login failed when trying to connect.

Then I changed password for sa and tried login as sa, but again get the same error:

I restarted SQL Server, but it didn't help. What I do wrong?