How To Fix Input Signal Out Of Range Change Settings To 1600x900-60hz

Used RDP via that setup locally and remotely for years. Locally RDP is available 24/7/365, when out of town, port forwarded and opened a high numbered port (49XXX) and forwarded it to the local machine IP:port 3389. Both setups, local and remote, worked perfectly--never had a problem. Therefor, I suspected it wasn't a problem with Windows Settings.