This incident has been resolved.

The root cause has been identified and a fix has been implemented. We are currently processing the queue that has built up over the past few days.
We expect to be in sync and processing new jobs rapidly from early next week.

We have seen an increase in plagiarism checks that are in processing status for a long time and seem not to complete with a valid result. We are together with third parties working on this issue as a top priority and hope that we have this sorted in not too long. We are sorry for the inconvenience caused.