You need to go into setting menu of Tivo under remote and set it up to accept third party control. I dont recall the name of the option but you will find it.
My Tivo Roamio has a "Network Remote Control" setting located in the Remote/CableCard/Devices menu. It allows remotes on your private network to control the Tivo.
Randy URC MX-890, MX-780, MX-450, R40, MX-500, Sony XBR-55X900E, Panny TC-P55ST60, Tivo Roamio Pro & Premiere & OTA, TWC Arris DVR, Onkyo 333 AVR, Roku Express 4K, Panasonic Blu-Ray