Error when adding a new derived SBC for Direct Routing: Cannot find specified Gateway

Symptoms

When adding a new derived Session Border Controller (SBC) for Direct Routing using New-CSOnlineVoiceRoute cmdlet, you receive this error message:

"Cannot find specified Gateway"

Cause

New domains must have at least one user enabled for Enterprise Voice to create a voice route for a derived SBC.

Resolution

Enable at least one user for Enterprise Voice in the newly verified domain. See the detailed steps here.