Parallel Submission Limit Reached

It’s been 6 days that we have been trying to submit to task 1, but it fails with the following message: “Submission failed: You have exceeded the allowed number of parallel submissions. Please wait until your other submission(s) are graded.” Can you help?
Thank you.

I also encountered the same problem, but on the submission list, there are still successful submissions, which is a little unfair.