Symptoms
In a Microsoft Skype for Business Server 2015 environment, assume that a Skype for Business on Mac user is a delegate of multiple delegators. The first time that the user tries to create a meeting in the Outlook for Mac client on behalf of a delegator, the process works. However, if the user soon after creates a meeting for a second delegator, the process fails.
Resolution
To fix this issue, install the August 2021 cumulative update 6.0.9319.619 for for Skype for Business Server 2015 and Unified Communications Managed API 5.0 Runtime.
