Apr 05, 2016 03:37 PM|Mikesdotnetting|LINK
You probably need to synchronise the user account your are trying to use with an existing SQL Server login on your server/machine. You can do this by running the following command against your database
sp_change_users_login 'update_one', 'user', 'user'
where 'user' is the name of the account you are trying to connect with.