I am getting a server error when I try to upload images, sound or I want to build .apk. Here is a video screencast link WeTransfer - Send Large Files & Share Photos Online - Up to 2GB Free.
The images I used are 174kb (the tutorial kitty.png) and with my jpeg 46Kb, the sound is a mp3 14KB.
I also tried to clean the browser cache, used other browsers (Chrome, Brave, Firefox, Edge) and with another account.
Find a different way to record and upload your session.
No one here wants to join a service to watch your screen cast.
