Came here looking for solutions to this myself. In my case the solution was easy and may help others. I had installed a new graphics card in the Debian server running the Channels DVR server and while installing the drivers the chromium package was uninstalled. From other posts in the forums here it has been confirmed that TVE requires the Chromium browser (e.g., https://community.getchannels.com/t/channels-and-chrome/37347/2). In any case, once I re-installed the Debian chromium browser the TVE error was fully resolved. I might suggest that anyone seeing this TVE error check that their Chromium browser is updated, as it undergoes frequent security updates. If Channels DVR is running in a docker image or under docker-compose, Chromium browser updates may be automatic and not run into this error.
I keep getting "No Login form found"
What the heck is that about?