I’ve solved my problems, at least for now (until Plex comes up with a new update). In the Plex Apps running on my TVs I changed the following in ‘settings’: go to ‘Advanced’ change parameter in ‘Allow Insecure Connections’ to ‘Always’ change parameter in ‘Prefer Insecure Connections’ to ‘Always’ return. It worked right away on my old Panasonic and Samsung TVs.