Having just completed my first highly available Sonus Cloud Link I just thought I would mention an error message I came across when installing the second appliance.
The Sonus Deployer tool showed a very nice red error message saying the Powershell module is not ready
This was also shown in the underlying PowerShell window
I had seen a similar message during the installation of the Skype Online Powershell module when you try to load it without having restarted, however the ASM server had been rebooted and I was able to load Skype for Business Online PowerShell module and connect to the tenant.
If you read all of the notices and guides you will see mention that the length of time it takes to deploy the second appliance is dependent on the connectivity and speed of the first, which led me to check the first appliance.
I then discovered that the Primary appliance actually had been configured as standalone! It was then a case of redeploying the CCE configuration, this time ensuring the HA Master option remained selected and then afterwards the second appliance was able to progress.
Lesson of this story, ensure you get the configuration correct on the Master appliance and make sure it is saved!