Recommend to create a Read-only SQL user for configuration in Crystal Report design. In order to run a stored procedure in a report, you will need to grant the required access rights to create/modify and execute stored procedure.
STEP 1 - At SQL Server - Security - Login : Create a new SQL User, eg. SAP_REPORT
STEP 2 - Server Roles, make sure new SQL user is assigned to public Role only.
Step 3 - User Mapping, select the relevant SAP Company Database and assign Read-only database Membership.
Step 4 - At the SAP Database, Create a new Security Group with below script:
-- Create New Role
CREATE ROLE db_storedprod;
GO
--Grant EXECUTE permission at the schema level.
GRANT EXECUTE ON SCHEMA::dbo TO db_storedprod;
GRANT CREATE PROCEDURE TO db_storedprod;
GRANT ALTER ON SCHEMA::dbo TO db_storedprod;
EXEC sp_addrolemember db_storedprod, SAP_REPORT
GO
Step 5 - Review the new user is mapped to new 'db_storedprod' security group.