Cisco Unity Connection via MRA Expressway Core HTTP allow list

 Deploying Expressway version 12.6 to support MRA and B2B calling with CUCM 11.5(1)SU8 I found voicemail was unavailable via the Jabber clients when connected via Expressway.  

The clients would indicate they couldn't connect to VMREST via 443.

The Unity Connection servers were discovered in Expressway Core (Configuration > Unified Communications > Unity Connection Servers) and the inbound rules seemed to be automatically populated (Configuration > Unified Communications > HTTP Allow List > Automatic Inbound Rules).

Regardless I found "Access Denied" messages in the Expressway Core event logs stating otherwise.

The fix was to seemingly replicate the rules manually (Configuration > Unified Communications > HTTP Allow List > Editable Inbound Rules).

To keep the list simple I used prefixes to VMREST on port 443 and the root on port 7080.