User & quot; sa & quot; login failure SQLServer error 18456 Solution

You can log on with a windows account.

Troubleshooting process:
Step 1: Start all SQL-related services, and the problem persists;
Step 2: view the windows Firewall, Which is started by default. If the option is Disabled, it is Disabled. The two prompts "due to security considerations, some settings are controlled by group policies" "Windows Firewall is using your domain Settings", first use gpedit. in the msc grouping Policy Editor, choose "Computer Configuration"> "management template"> "network"> "network connection"> "Windows Firewall"> "standard configuration file". Check that the properties of each option on the right are not configured. The problem is not here.
As mentioned in another prompt, the domain settings cannot disable SQL Server, and I check that the local open ports (netstart-an), 1434, and are all in the development status.

Dizzy, will it be a wrong password?

Step 3: log on with a windows Account. After the connection is successful, select "properties ",
Right-click the instance, and in the "properties" window, go to the "Security" item, and check that "SQL Server and Windows Authentication Mode" is set in "Server Authentication ",
Run the following statement to enable the sa user and change the sa password.
EXEC sp_password 'sa ', null, 'sa'
Alter login sa ENABLE

Execution error:
Message 15116, level 16, state 1, 1st rows
Password validity Verification Failed. The password is too short to comply with Windows policy requirements.

Haha, find the problem.

Local Settings may be overwritten by domain settings. The security policy is specified in the domain settings, and the password must be complex. Change the sa password again,
EXEC sp_password 'sa ', 'iop _ 098Mn', 'sa'
Alter login sa ENABLE

Solve the problem!