App approvals are entirely managed by monday.com itself through its accounts system, depending on your permissions setup.
Apps are not involved in it. As a consequence, we can’t offer any fix for this kind of issues.
Thus said, we strongly advice to repeat the procedure and ask your admin to double-check their notification inbox.
If your admin (or you, as an admin) can't find the approval request notification, please contact monday.com support.
If they reply that you should contact the app vendor to get support on this subject, it is likely to be an automated response. In this case, please persist with them. They’ll eventually provide assistance.