Our current app is not supported on non 4k/UHD sets. neither of those seem to be. https://support.plex.tv/articles/204080173-which-smart-tv-models-are-supported/
Support for those TVs would have officially ended a while ago but the Netcast one probably stopped working due to the recent depreciation of TLS 1.0 security. Plex support is ending 2020-09-30 on older smart TV devices
