On installation tutorial in step regarding to creating database on MS SQL Server, after the database and user with specific permission are created please do also the following actions.

Go to Microsoft management studio . Open the REDMINE database and then open the security folder and find REDMINE user in it.

Give the selected permission to REDMINE user in section role_members (like You can see in attach).

Also please NOTE : Use IP adresess for host in database configuration files. (database.yml)

*DOWN BELOW YOU CAN FIND THE SECTION FROM REDMINE INSTALLATION TUTORIAL for which the problem is manifested **************************************

SQL Server
The database, login and user can be created within SQL Server Management Studio with a few clicks.

If you prefer the command line option with SQLCMD, here's some basic example:

Hide SQL

USE [master]
GO

-- Very basic DB creation
CREATE DATABASE [REDMINE]
GO

-- Creation of a login with SQL Server login/password authentication and no password expiration policy
CREATE LOGIN [REDMINE] WITH PASSWORD=N'redminepassword', DEFAULT_DATABASE=[REDMINE], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF
GO

-- User creation using previously created login authentication
USE [REDMINE]
GO
CREATE USER [REDMINE] FOR LOGIN [REDMINE]
GO
-- User permissions set via roles
EXEC sp_addrolemember N'db_datareader', N'REDMINE'
GO
EXEC sp_addrolemember N'db_datawriter', N'REDMINE'
GO