When I access the secure print section of my "mailbox" on the server some jobs won't print. I can select and ask for the printout, but nothing is printed. After this the job remains in the mailbox.
Other jobs, present at the same time in the mailbox, print without any issue.
Try as admin, if they still won't, delete them. While there is no way to prove it, I think it is safe to assume the jobs are corrupted for some unknown reason.