Fix SQL Error : SQL Server Error 25 And 87


Error SQL Server Error 25 And 87 is very known error while connecting through MS SQL Management Studio. SQL Server Error 25 And 87 comes out commonly when we type wrong host name instead of correct host name (server name). I have already provided resolution in my earlier article SQL error of Could not open a connection to SQL Server and Login failed for user iis apppool default apppool. I have provided main key factors how we can resolve this issue through given below steps.

Error Description

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 25 - Connection string is not valid) (Microsoft SQL Server, Error: 87).

Step 1: Login Authentication Windows or SQL Server

Check your login Authentication whether its Windows or SQL Server.

Step 2: Use (.) (dot) instead of complete server name

If you are using local MS sql database then you can use (.) (dot) instead of complete server name.

Step 3: Enter Correct Host Name

Enter your correct host name: (hostname\SQLEXPRESS) my_hostname\SQLEXPRESS (in case of SQL Server Express) or (my_hostname\mssqlserver).

Step 4: Try localhost slash (\) then host name

You can also try localhost slash (\) then host name, here is sample as (localhost\SQLEXPRESS) or (localhost\mssqlserver).

Authentication Windows or SQL Server
Fig 1: Authentication Windows or SQL-Server
SQL Authentication using dot
Fig 2: SQL-Authentication using dot
Authentication Windows or SQL Server
Fig 3: Use localhost in server-name


Explained all primitive steps to resolve very known SQL Server Error 25 And 87. You may go one by one steps provided to resolve this issue so that take over from this SQL error.

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