Microsoft SQL Server Error 18456 Login Failed for User

18456 Error Problem

So I was connecting to Microsoft SQL Server and trying to use the SQL Authentication method and I received this event ID error 18456 login failed for user you provided. See below example.

I did some research online and found out that this usually means that your connection request was successfully received by the server name you specified [so why didn't it work], but the server is not able to grant you access for a number of reasons and throws error: 18456.

Below is a list of reasons and some brief explanation what to do:
SQL Authentication not enabled: If you use SQL Login for the first time on SQL Server instance than very often error 18456 occurs because Windows Authentication (only) is set in Server properties (security section).

To Access Server Properties, Open SQL Server Management Studio, go to Object Explorer pane (use view if you can’t see it). Use the connect button to connect to database engine for your server. Once connected you will see it in object explorer. Right click server and click properties. Server Properties window will appear.

See below screenshot that might be causing SQL login to fail

You should set Server Authentication to SQL Server Windows Authentication 

Invalid userID: SQL Server is not able to find the specified UserID on the server you are trying to get. The most common cause is that this userID hasn’t been granted access on the server but this could be also a simple typo or you accidentally are trying to connect to different server (Typical if you use more than one server)

Invalid password: Wrong password or just a typo. Remember that this username can have different passwords on different servers.

less common errors: The userID might be disabled on the server. Windows login was provided for SQL Authentication (change to Windows Authentication. If you use SSMS you might have to run as different user to use this option). Password might have expired and probably several other reasons…. If you know of any other ones let me know.

18456 state 1 explanations: Usually Microsoft SQL Server will give you error state 1 which actually does not mean anything apart from that you have 18456 error. State 1 is used to hide actual state in order to protect the system, which to me makes sense. Below is a list with all different states and for more information about retrieving accurate states visit Understanding “login failed” (Error 18456) error messages in SQL Server 2005

ERROR STATE	ERROR DESCRIPTION
State 2 and State 5	Invalid userid
State 6	Attempt to use a Windows login name with SQL Authentication
State 7	Login disabled and password mismatch
State 8	Password mismatch
State 9	Invalid password
State 11 and State 12	Valid login but server access failure
State 13	SQL Server service paused
State 18	Change password required