I assume you checked the batteries in the remote. I had two friends buy Harmony remotes and both failed within a year, so not sure I'd be too quick to blame the Rotel. Maybe try unplugging the receiver for a minute and then try again.
Rotel RSX-1058 Won't Respond to Remote Commands
Have any forum members experienced a situation where your Rotel receiver suddenly stopped responding to remote commands? I haven't made any changes to my system, set-up or remote (I use a Logitech Harmony One) but my receiver is unresponsive to any and all remote commands. I haven't been able to find the OEM remote to perform a test but it seems more likely to be a problem with the receiver; it worked perfectly one minute than it just suddenly stopped responding. Any info on similar experiences is appreciated.