You are stuck and the Link Essential installation is incomplete because you are being told it is already installed.
1. My Link Essential is already linked to my account, but at another location
You'll need to ensure that the Link Essential is not already installed at another location. To do that, go to the home page for your account in the Somfy Protect app. Click on the arrow at the top of the page. This menu lets you access all the locations associated with your account. Delete the incorrect location and keep the one where the Link Essentialis installed, then continue the installation.
2. I have multiple email addresses, and I am using the wrong one to access my alarm
I am not logged into the right account, so I am being directed to install my equipment. I get this error message when the Link Essential is already installed. Follow the instructions in this article: Why is my account empty when my alarm has already been installed?
3. Upon the 1st installation, I get this message
Your Link Essential is new and you are installing it, but you get this message. Contact customer service.