Hi @Doug Mann ,
it seems that the exception you encounter may be about the permission.
You can grant permission to specific object:
Please login with an admin user that have rights to change execute permissions:
GRANT EXECUTE ON [dbo].[XXXXX] TO [UserYY]
Grant permission to db_owner role:
Open SSMS>>Security>>Logins>>go to properties of user
Click to User Mapping>>check the database where you are going to give the db_owner role
Below this on Database role membership select db_owner role
Create a new database role:
CREATE ROLE db_executor
--grant the role exector permission
GRANT EXECUTE TO db_executor
Giving everybody execution permission, but this is an extreme solution
GRANT Execute on [dbo].your_object to [public]
Grant sysadmin server role to the user:
Open SSMS>>Security>>Logins>>go to properties of user
On Server Roles section check sysadmin
and the best practices of Row Level Security you can refer to:https://learn.microsoft.com/en-us/sql/relational-databases/security/row-level-security?view=sql-server-ver15#Best