Have a Sony Grand Wega KDF60XBR950 HD TV (13 years old) & 60" screen. Trying to connect to Roku 3 with quality converter box. Can pull up menu add channels & do all with display working until start to play movie etc. Get purple screen 'HDCP unauthorized. Content disabled'. Has sound. All new cables that have been checked on other devices, everything unplugged & used other ports on TV (has 7). Box works on other TV & other box gets same message this TV. ROKU support went through what is on their website that we had already done. Says cables weren't 2.2 & other stuff & I think they don't know. Tried Ethernet (best Powerline available) instead of wireless. Still same. TV too good to not use. Any ideas appreciated.