By default, only sysadmins on the SQL server which contains the data warehouse database can read the database through Jet Essentials. In order for other users to be able to access the information in this database, you need to explicitly grant them permission using SQL Server Management Studio.
Open SQL Server Management Studio and connect to the Database Engine on which the Jet Data Warehouse database is located.
Once connected to the Database Engine, open the Security node by clicking the + sign.
Once the Security node is open, click the + sign next to the Logins node.
Locate the user that you would like to grant permission to. They may or may not be in the list of Logins. If they are not, there are typically two ways to handle security administration for this task.
1) Add the individual user as a new login
2) Add an active directory group containing the user's login and other data warehouse users
To do this, right click on "Logins" and select "New Login..."
Add the user's windows login or active directory group name in the "Login name" box .
After specifying the Login Name, click on the User Mapping page and find the Jet Data Warehouse database. Click the check mark on the "Map" column to map the user to the database and within the list of roles below select "db_datareader"
Click okay and allow the changes to be process. Once the changes have been made, the added users will be able to either write or run reports in Jet Essentials once the data source has been set up. This process will need to be repeated for any new users, unless using the active directory group option.