You're trying to upload a file larger than 4 GB (e.g., a very large video file), which isn't currently supported.
You can paste EAXTRP5F into the search bar in All Fields & Tags mode to find the attachment in question. You'll need to delete it and empty the trash. If you don't have another copy, you can Show File and move the file somewhere else on your computer and then add it back as a linked-file attachment.
Upgrade Storage
You can paste EAXTRP5F into the search bar in All Fields & Tags mode to find the attachment in question. You'll need to delete it and empty the trash. If you don't have another copy, you can Show File and move the file somewhere else on your computer and then add it back as a linked-file attachment.