PDF to PDF/A Convertion does not work

You say it hangs. What exactly does that mean? What do you see? OCR is a time consuming task and it sometimes takes a bit longer to get your job processed. Leave the status window open and wait until processing finishes. Sometimes our OCR backend is a bit busy. All jobs are queued and we process them in order and this could take a couple of minutes. We know that there are some peaks and we will increase our worker machines in the near future.