Sorry for the delay in responding.
Sharing your log file is great, thanks. As an FYI, you can attach logs and other small files (including screenshots and images) here directly without needing a file sharing service.
Before I do what I did in my last answer where I gave a fair amount of info for the windows OS, more info is needed. Like, as much as you can give. For instance, lets start with:
What is your Operating System and basic system specs?
What version of Shotcut?
Have you recently upgraded Shotcut?
Does this only happen on this particular project? i.e can you create a new project with a short simple video and successfully export that? Can you open an old project and export that?
If you are using windows, has anything changed recently? Take a look here and if you are using Windows, then follow these reinstallation instructions precisely to the letter (including registry cleaning and folder deletion).
I had a quick look at your log and it is slightly weird. Another thing to try is to create markers and export them.
Try this: Divide your video into 3 equally divided markers and export the first, then the second, and then the third. If is a part of the video or a filter/transition borking the export, then some markers will complete and the one with the issues will fail. Then you can drill down on the problem component (sometimes recreating a transition or filter is necessary).