I am just posting something that may be interested to someone else struggling with the install of Reporting Services on multiple servers.
Imagine the following scenario : You install your database server, then you install a first instance of Reporting Services on the second server, and then, finally, you install a second instance of Reporting Services on yet another server.
If you do it like this, you are on the wrong way. There are lot of chances that you receive, when you will access the http://servername/rsreportmanager site, a RSReportServerNotActivated error on one of the two server. The problem is that report servers are paired with the database server in order to avoid, for example, other report servers accessing the same database and getting data they should not see.
For this purpose, a symmetrical key must be exchanged between the database and all the report servers in the farm. But, if you read the documentation, you will see that the only thing you have to do is to activate the report server. So, let's do it using the rsactivate command. But, bad luck, you receive an error saying the "Local NT Service account is not enabled". What you want to do then ? Looking for the activation of such account ? Changing the account with which the report server service is running ? Not at all. Rather than following the error message, delete the key and the association for this server by using the rskeymgmt -d command. Then, you have to configure the server using the rsconfig command and finally the rsactivate one.
Hum, well, not sure Now, try to access the local report server website. It will work. Great ! But, try to access the report server website for one of the other server. You will certainly receive a "Bad data" error. If you have some experiences with .NET, "Bad Data" should give you a bit of information, leading you to some cryptographic error...Right ?
The final word of this story is the following : When you want to activate servers in a farm, first activate the local one, then activate the others remotely. As said in this documentation, you must execute the rsactivate command from the same server.
This took me a bit of time to understand this, but at the end it is pretty meaningfull why you have to do it this way and I hope I saved time to others