exception 306003: Authorization failed in Calculation Engine. User is not authorized to ‘SELECT’

So I am encountering this error when generating a BEx query in Analysis for Office Excel. The query uses a HANA calculation view.

We’ve already checked the privileges of the HANA user (SELECT on _SYS_BI, EXECUTE on REPOSITORY_REST(SYS), REPO.READ) and they are all checked with the Grantable to Others option set to No.

For the BW user, we’ve already added the missing roles and authorizations identified by traces but the issue still persists.

What else could we be missing? Thanks in advance for any response. It would be greatly appreciated and a big help.