There are missing files in your project

[Hudson555x]

Set your video mode to the video mode you want. Right now how have it set to “Automatic”. You can change that via Settings - Video Mode
[Language: English]

I’m not sure the exact progression from “2.mlt” to your current file.
It’s unclear what video mode you had set in “2.mlt”>
The file you uploaded has “Automatic” set for a video mode.

To learn more about the Video Mode read this:

Video Mode

Introduction Video Mode is the project resolution, aspect ratio, frame rate, and color space. It is important to set this as you desire at the beginning of your project. If you try to change it later Shotcut will try to retain the timing of edits, but some users have reported problems, and it is risky. Also, at this time Shotcut will not automatically adjust anything for you related to size and positioning of elements like text and picture-in-picture when changing resolution. You can think of…