We have Unity 5.X with Failover ( 2 Nodes). On the failover server - with automatic failover configured. The message " This Cisco Unity server is an inactive failover server. Most pages will not let you make changes. To make changes, use your active server XXXXXXXXX.
Changes can be made to the Integration, Ports, and Voice Recognition pages, if applicable"
Is this normal?
This is expected behaviour :) You have to keep in mind that in the "Failover" relationship, the Primary server is considered the Publisher and the Secondary server is the Subscriber. Most changes are made on the Publisher and replicated across to the secondary or "Failover" server.
You can test this out using the steps in this guide;
Hope this helps!