Apparently Direct SIP is not possible on the v14 Virtual PBX in multi-tenant mode. (confirmed by tech support) I can find no mention of this change in any posts from 3CX. So is this by design? Or is it possible that the feature may reappear in the future? For me, this is a bit of a blow, as it will mean having to abandon my multi-tenant strategy; my IVR will be receiving calls via Direct SIP, from my client's customer service PBX. On a single instance installation, the Settings \ Network \ FQDN tab has a setting "Allow calls from/to external SIP URIs" and you can set the local SIP domain. Multi-tenant does not have this tab, and the setting is not available in the 3CX Virtual PBX Manager.