When you are trying to connect to the database using the Microsoft SQL Server Management Studio, below error coming out.
You have to create and assign the necessary authorization for this user.
1. Login to the SQL Server Studio using the sa user or use other users which are authorized if you have any. In our case, we have other user (Administrator) which is capable to access the SQL Server Studio.
2. Once logged, click on Logins folder. From here, you will see all the users that having access / authorization to the database. Some cases, the user is already created but lack of authorization. You might just need to assign the missing authorization to enable the access.
3. Next, follow the steps from article, How to Grant User / Group Access to SQL Server Database. You should be able to access once the user is created and assigned with the necessary authorization.