Before proceeding, Save As, and rename your existing project to a different file name as a backup.
You are requesting help on an outdated version of Shotcut: version 20.09.27
Latest version can be downloaded here: Shotcut - Download
The export error log is giving you an error code: Failed with exit code -1073741819
In your screenshot it shows:
Something at this time code failed, from what others have reported, it could be a filter, transition. Go to 1:31 on your timeline and try removing filters one by one to see what is causing it. Most likely you’ll just have to delete the filter and reapply it. Or delete a transition, then remake it.
In Shotcut there is a convert to edit-friendly option for files that have a variable frame rate. Click on the clip then in the properties window click on the three line stack.
Exit code such as yours (and other exit codes) can be found in the post below for reference.