It seems you try to upload MOV file. This is a Beta feature. Hence you might face som trouble.
The request to retry again failed once.
As a hack - If your clip is playing on Chrome Browser, you should be able to upload your clip seamlessly on platform. So try once no Chrome browser.
Generally Videos made via iPhone are not supportive on the platform. Due to codec issues. As a workaround, we suggest you use one of these free online tools to convert your video to MP4 / M4V / WEBM format. So you can use cloudconvert.com for easy conversion.
Appreciate your understanding. The team is working on a plan to accommodate other different file formats & should you expect the same in the coming months of 2024.