Microsoft SQLServer Error 233: Causes and Solutions Explained

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Users get the Microsoft SQL Server error 233 when logging into an existing database. It develops for various factors, such as going over the connection limit or firewall limitations. Even after entering the correct login information, users frequently report being unable to connect to an existing database.

To fix the Microsoft SQL Server Error 233, try the following ways:

  • Activating TCP/IP
  • Enabling SMP(Shared Memory Protocol)
  • Enable Named Pipes Protocol
  • Enable the virtual interface adapter.
  • Change viewport
  • Checking for remote connection
  • By overcoming The Limit For Connections

Microsoft SQL Server

We can resolve users’ errors when authenticating to Microsoft SQL Server using minor modifications. So let’s see these ways in detail.

How to Fix Microsoft SQL Server Error 233? 

The following options in SQL Configuration Manager can be checked and enabled as one of the potential solutions to SQL server error 233, as will be detailed below.

Fix Microsoft SQL server error 233

Not configured for Mixed mode on Microsoft SQL server

Administrators can utilize their username and password separately following a specific procedure. You can also use the login and password for SQL servers with the aid of mixed mode. The option may occasionally be deactivated, which results in the Microsoft SQL Server 233 error.

By attempting to connect to SQL Server Management Studio with the System administrator account, you can determine what led to this issue.

Log in to SQL Server Management Studio> then server right click>then click on properties>then click on security>Change Windows Authentication Mode from SQL Server to Windows Authentication>then ok>then click on restart.

TCP/IP protocol disabled

Here, you should activate TCP/IP by following the steps below:-

Go to Microsoft SQL Server>then look for configuration tools so that you may choose both SQL Server Configuration Manager and SQL Server Network Configuration>then click on TCP/IP to enable it.

Shared memory protocol disabled

Users widely use shared Memory Protocols to connect to SQL Server instances. There will always be an authentication error if SMP is disabled.

Microsoft SQL Server Error

In this case, we need to enable SMP by following the steps.

Go to MS SQL Server>then configuration tools>then choose SQL server network configuration>then click on shared memory>then click on enable.

Disable of named pipes protocol

Named pipers protocols ensure a local area network’s excellent connection. Moreover, memory assists in the transmission of information from one area to another. You will encounter a problem if you deactivate Named Pipes Protocol. So we have to Enable Named Pipes Protocol to fix it.

Go to the SQL Server configuration manager>, click on SQL Server network configuration>, click on named pipes protocol>, and click on enable.

Disable of virtual interface adapter

Users face a Microsoft SQL server error 233 when the virtual interface adaptor is disabled. So to fix this issue, we have to enable the virtual interface adapter.

Go to the SQL Server configuration manager>, click on SQL Server network configuration>, and click on enable virtual interface adapter.

Viewport in Windows firewall

To achieve robust connectivity, we have to alter the viewport.

Open the Control Panel of your system>click on Windows Firewall>then Settings> then click on Exception>select add port> a window appears now fill up the port number> then click ok>then click on enable SQL.

Check for remote connection

To connect to the SQL server remotely, a remote connection is essential. As a result, it might cause Microsoft SQL server error 233 on a remote connection. Please do the following steps to make it enabled.

Error connection

Click on server node>choose properties> Select Connection (Left Tab)>then click the option ‘Allow remote connections to this server.’

Overcoming the Limit for Connections

A connection number will appear as 32767. To create a new connection and increase the number of connections, set it to 0. There is no restriction against using an existing link now that you have established a new one. Both the latest and the current relationship may be used at once. This is a short-term solution for exceeding the connection number limit. For a permanent solution, follow the below steps. 

Go to the SQL Server management studio>click on SQL Server Instance>click on properties> Change in Server-level> Select connection tab> Increase connection number limit>then restart.

See also: How To Import A Large SQL File In XAMPP?


How can I confirm that SQL Server supports remote connections?

Select the 'SQL Server and Windows Authentication' mode on the Security tab for Server Authentication. Once 'Allow remote connections to this server' is ticked, go to the Connections panel and click OK.

How can SQL Server configuration be fixed?

Using the SQL Server installation disc, run the setup.exe file of the SQL Server setup application. After completing the prerequisites and system verification, the Setup application will display the SQL Server Installation Center page. To begin the repair process, click Repair after clicking Maintenance in the left-hand navigation bar.

How can I make IP connections to SQL Server possible?

Right-click SQL Server Configuration Manager after expanding the Configuration Tools subdirectory. Run as Administrator by selecting it. Click Protocols for SMTKINGDOM under SQL Server Network Configuration. Right-click TCP/IP in the right pane and select Enable.

What is a change in an authorisation policy?

Authorization for Audits Policy You may audit changes made to resource characteristics, security token object permissions, the assignment and removal of user rights, user rights policies, and the Central Access Policy for file system objects.

What is the largest SQL Server error log file size allowed?

A log file may have a maximum size of two terabytes. Enable Autogrowth to allow the SQL Server to increase database file size when space becomes an issue.

How Can I Find SQL Server Deadlock Queries?

In SQL Server, several methods exist for finding the queries creating deadlocks. Using SQL Server Trace Flag 1222 to record the deadlock information in the SQL Server Error Log is one of the solutions available.

How can I obtain the SQL Server deadlock log?

SQL Server Profiler can help you figure out why a stalemate occurs. When two or more threads, or processes, are cyclically dependent on each other for a certain set of SQL Server resources, a deadlock results. You may build a trace in SQL Server Profiler that captures, replays, and visualizes deadlock occurrences for examination.

What distinguishes a local login from a domain login?

Access to resources on the local computer or resources on networked machines is made possible via a local login. The Winlogon capability tries to log on to the domain if the computer is joined to one. A user can access both local and domain resources with a domain login.

How do I connect in database mode?

Click on your name in the top left corner of the Mode home page for the Workspace to which you want to add the connection. Then choose to Connect a Database. The database you want to use from the list.

How can I modify the SQL Server IP?

Right-click the SQL Server Instance in the Server Name category on the right pane and choose Properties to display the Properties dialog box. Modify the IP address resource under the General tab.

How is SQL Server restarted?

Select SQL Server Services in the left pane of SQL Server Configuration Manager. Right-click SQL Server (MSSQLServer) or a specified instance in the results pane and then choose Start, Stop, Pause, Resume, or Restart.

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