CommandFusion iViewer can communicate with Crestron processors in a variety of ways:
Documentation for each method is available on their respective GitHub repositories.
Each method has pros and cons, which have been discussed quite frequently on the CommandFusion Software Google Group.
In Summary:
For first time integration with Crestron, we recommend this approach.
Not recommended for 3 series products. Choose the Crestron Mobile method above if you are using 3 series processors.
Firstly, make sure you are using the latest version of iViewer 4 (not CF iViewer). If the problem persists - contact us via one of the options on our support page.