Fix Login Failed for user – Microsoft SQL Server Error 18456 Instantly

Written By Kumar Raj
Anuraag Singh
Approved By Anuraag Singh
Published On March 14th, 2024
Reading Time 6 Minutes Reading

SQL error 18456

Help! I am getting this error ‘Microsoft SQL Server error 18456: Login failed for User’ while trying to connect with SQL Server. Can anybody explain why is this SQL error 18456 : login failed for user as is occurring. 

SQL Error Message

I have two servers hosted on the same machine, each has its own IP address. However, SQL Server is configured and execute on both virtual servers. Even though, host forgot to mention which of the servers is in Web and which is in SQL authentication mode. So, I considered that first is in the Web, and second is SQL. But when I tried to connect with Server, I received the SQL Server 18456 error message. Can anybody tell me what is Login failed for user Microsoft SQL Server error 18456 State 58 means and how to fix it.

What is 18456 SQL Server Authentication Error in Database?

Generally, when an error code displays on the screen it gives the description of what has turned out gone. Unfortunately, if there should be an occurrence of error 18456 SQL Server authentication on screen, no reason for login failure is mentioned.

Microsoft SQL Server Error 18456 Login failed for User ‘sa’ is quite common technical glitch encountered due to varied reasons. This issue might be occurs when you type incorrect user name or password . It can be possible that due to some unexpected reasons, the login permission cannot be granted to the users. As a result, the user does not have permission to use SQL database.

Therefore, in this post, we will walk through on how to resolve this error. In continuing with the troubleshooting methods, we will also discuss the reason behind this error. So, users will understand the causes and prevent Server from the future disaster.

Login Failed for User (Microsoft SQL Server Error 18456) – Potential Reasons

In this section, the possible causes of this user authentication failed error are listed below. Users can go through it and prohibit this issue in the future.

  • It might be possible that login may be in a SQL Server login mode. But the SQL Server might be set to Windows Authentication mode. Thus, whenever the user uses SQL login, then it is very often to get error Login failed for user Microsoft SQL Server Error 18456 state 58.
  • When users try to connect with Database Engine using SQL Server Authentication. However, user login does not exist in the SQL Server database.
  • It is also a situation when the Windows Authentication mode is set to SQL login. But the user login is an unrecognized Windows principal. It means that Windows is unable to verify the SQL login ID. This situation when Windows login is from an un-trusted domain connection.

After understanding the probable causes, let us look at the resolution techniques. But first understand the various states occur while getting SQL error 18456. According to the states, you need to use the workarounds.

SQL Server Error 18456 – Check the State Number

Before exploring the method, first check the state of the error in the SQL Server error log. Actually, this message has different state and each having different resolution technique. So, first verify the state and the root cause of the glitch.

Error State Description
2 Users ID is no longer valid
5 Same as above
6 Using Windows login name with SQL Server authentication
7 Login is disabled/Turn-off
8 Mentioned login Password is incorrect
9 Entered Password is not valid
11 Server Access Failed
12 Credentials is valid, but server access is not responding
18 Login password can be modified

Login failed for user comes in STATE 6, where there is a problem with Server authentication. Let’s look at the fix of this.

Also Read: Fix SQL Server Error 5242 With Ease

How to Fix Login Failed for User (Microsoft SQL Server Error 18456) Easily & Accurately

In the following segment, user will get the accurate solution on SQL Server 18456 error. Even, in the situation when the SQL Server is in SQL Server Authentication Mode and unable to connect to database with User and SA Login. This can be done with the help of SysTools  SQL Password Recovery Software. Just go through this video and know how the tool fix SQL Server 18456 problem.

Download Tool Purchase Now

Step-1 Download, Install and Launch the software in system.

launch tool

Step-2 Click the Browse button to Add Master Data Files here.

browse MDF

Step-3 Now, Preview the User Login Details to proceed further.

preview login details

Step-4 Click on the Reset button to reset the user password here.

reset login details

Step-5 Finally, Hit the OK button to finish up solving SQL error 18456.

click ok to fix SQL error 18456

Now, users can also take help from the video tutorial of the software:

It is an incredible utility that remove the SQL Login password of User & SA too within few mouse clicks. All you need to do is to provide master.mdf file and rest of the process done automatically by software. Going through this video, users can easily solve their login failed for user ‘sa’ issue.

Also Read: Can We Solve SQL Server 825 Error With Ease?

Fix 18456 SQL Server Authentication Error with SSMS

In case, users are not comfortable in fixing the issues using the automated software, they can opt for the manual solution as well. However, this SSMS (SQL Server Management Studio) solution is not able to surpass the automated tool. However, users with SQL server proficiency are comfortable with this solution.

This method to fix error 18456 SQL Server authentication, requires just three major steps mentioned below for users to get the desired solution.

Step 1. Using SSMS / SQL Server Management Studio

  • The first step is to Launch the SQL Server Management Studio in the system. 

  • Now, Right-Click the Database & Navigate to Properties option from here.

Users must note that an active SQL Server licence & SQL Server Management Studio application is necessary for them to undergo this operation.

Step 2. Select the Authentication Mode for SQL Server

  • Go to the Security tab from here & then Select the Radio button with “SQL Server and Windows Authentication mode” option.
  • Click on the OK button to close the page & proceed to fix Microsoft SQL Server Error 18456.
  • Now, Restart the SQL Server Services as you might be displayed this message by your server.

Step 3. SQL Server Configuration Manager to Log in with SA User

  • Open the SQL Server configuration Manager now to proceed.
  • After this, just Restart MSSQLSERVER to fix SQL error 18456 in database.

Now, users can Login with SA User without any hassles.

Also Read: How to Fix SQL Server Error 823 without Hassles


Login Failed for User (Microsoft SQL Server Error 18456) message is a very common glitch appeared in SQL Server. This problem can be easily resolved by the above-mentioned method in a systematic way. Furthermore, it is helpful to successfully reset forgotten SA password of Microsoft SQL Server without any fail.


By Kumar Raj

A versatile writer with the vast knowledge of technology helps to reduce the gap between a user and technology. Provides easy and reliable ways to resolve multiple technical issues, which users encounter in their day-to-day life.