Getting access denied error when enabling mailbox although the same admin has already added many mailboxes in exchange 2016

Question

Unable to enable mailbox via cloudpanel. The user has full admin rights over exchange 2016 and infact the same user has already created around 50 accounts..

KMI Support · Accepted Answer

This access denied error is because the IIS application pool that CloudPanel is using isn't running as a domain admin / user with exchange rights OR because basic authentication isn't enabled on the powershell virtual directory (after upgrading exchange that can?get?reset)

[Solved] Getting access denied error when enabling mailbox although the same admin has already added many mailboxes in exchange 2016