SQL Server Error 18456

The first step,

Scenario where the error occurred

Step Two,

Find the cause of the error

1th Step,

View the Windows log file. Run the input eventvwr (Event Viewer) to open the log file Viewer,

The third step,

Solution, from the second step we can see that the authentication mode of SQL Server is causing the problem, so just change it.

1th,

SQL Server Properties

2nd,

Select and certify the mode.

Fourth Step,

Restart the SQL Server service. I have a SQL Server instance named MSSQLSERVER on this machine

net stop MSSQLSERVER

net start MSSQLSERVER

Fifth Step,

It can be used.

SQL Server Error 18456