Hi there,
Our apologies that your final assessment submission wasn't collected on your first attempt!
We've had a handful of users who are on Windows XP report this issue when submitting their final assessment in Firefox, specifically. If you're able, we'd recommend taking the final assessment using Google Chrome as a workaround while we continue to investigate the cause. I know it takes additional time and effort to retake the assessment, so again, our sincere apologies.
Please let us know if using Google Chrome does not resolve the issue.
Christina from the Analytics Academy course staff