Hello, I had an issue installing Nintex Workflow & Nintex Live on our test server. The installer completed successfully, but there were errors in the Event Viewer when starting the service from Central Admin. After talking to Nintex support, they mentioned that there should have been a windows service "Nintex Live Relay Service". But it was not listed. So I re-installed Nintex, and when it was complete, I looked at the logs hoping to see more information about the service. Luckily, its location was listed, so I used installutil.exe to manually install it. I posting this, hoping it will save time for other users. Open command prompt, run as Admin:
installutil "C:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\BIN\NintexLive\Nintex.Live.RelayService.exe"
Go in Central Admin, System Settings, Manage Services on Server, and start Nintex Live Relay service.