Hi Rehana, In this case is Candlepin sending an event for us to delete that particular pool? If we don't receive such an event then I suspect the pool will stick around and raise this error. If you're not sure perhaps a candlepin engineer will know!
Adding needinfo for Rehana based upon comment 5.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Satellite 6.7.5 Async Bug Fix Update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2020:4346