This is all probably related to an FFMPEG setup that is not working properly. Its a bit hard to say without logging in and poking around, especially the missing file extension is a bit dodgy. But mobile devices and how they upload is a bit of a minefield and depends a lot on the device, browser and versions. PoodLL can probably handle it regardless if you specify the FFMPEG conversion parameters ... provided FFMPEG is working.
The video recording relies on a Red5 server, and tokyo.poodll.com is the one that most people use. FFMPEG working or not, the video recording goes via Red5 (for desktop machines) so the greyed out controls and red cross won't be solved by fixing FFMPEG. You will need a working red5 server with PoodLL installed on it. You can set up your own to get around privacy restrictions, but its a bit a technical. I have attached 2 PDFs, a "how to" on RED5 + PoodLL set up and a "how to" for FFMPEG + PoodLL set up. If you want me to do the setup, then it becomes a commercial discussion and those need to take place off-forum. So message me in that case.