Issues with upgrading 5.6 mysql rds to 5.7

Hi, I'm trying to upgrade our 5.6 mysql rds server to 5.7 but the preupgrade logs keep stating that there is a orphan table issue, however, when we do a search for the table the server shows that table does not exists. We have tried searching for the orphan tables but nothing comes up. Any ideas of what the problem might be?