Use Group Managed Service Account for SSRS We have a production environment running SQL Reporting Services 2014. The service is running as a group managed service account domain\SSRSProdSvc$
We are now trying to change our test environment to use managed service accounts for SSRS, however I can't change it.
If I go into Reporting Services Configuration Manager and try and change the service account I get an error

Setting Windows Service Identity to Windows Account
The Windows account information used to run the Windows service has failed to update. Previously designated settings are being used instead.

If I go into Windows Services I can change the account to domain\SSRSTestSvc$ and the service starts, however in the Reporting Services Configuration Manager it still comes up with the previous domain account.
I'm not sure how it was configured on Live, but when I look at the Reporting Services Configuration Manager it's service account is domain\SSRSProdSvc$
Any ideas how to fix test?
Try removing the managed service account like so by running the following command on your local SQL/SSRS Server:

Remove-ADComputerServiceAccount -Identity [Your Server Name] -ServiceAccount domain\SSRSProdSvc$


https://technet.microsoft.com/en-us/library/dd378979(v=ws.10).aspx

And if this hasn't been done, add the new managed account to the local server:


  
  On the domain controller, click Start, and then click Run. In the Open box, type dsa.msc, and then click OK to open the Active Directory Users and Computers snap-in. Confirm that the Managed Service Account container exists.
  Click Start, click All Programs, click Windows PowerShell 2.0, and then click the Windows PowerShell icon.
  Run the following command: New-ADServiceAccount [-SAMAccountName ] [-Path ].
  Associate the new MSA to the computer account by running the following command: Add-ADComputerServiceAccount [-Identity] &lt;ADComputer&gt; &lt;ADServiceAccount[]&gt;
  
  See Add-ADComputerServiceAccount for the complete syntax.
  


per Microsoft:
https://technet.microsoft.com/en-us/library/dd548356(v=ws.10).aspx