Prerequisite: Set up a user for enterprise voice OCS call bridge. Follow the below link to complete the steps required for setting up a user for enterprise voice OCS call bridge Setting up a user for Enterprise Voice OCS Call Bridge
Follow these steps to add rights to create an OCS call bridge:
Step 1) Open the properties of the user in the ADUC.
Step 2) Under the “Communications” tab, select “Meeting Settings”.
Step 3) Select the “High” or “Medium High” Live Meeting policy.
Only the High and Medium High policies have Enterprise voice enabled.