When a red cross appears in the Box Office icon it means the printer has no iternet connection. Switch the printer off and on again, making sure that all the cables are correctly plugged in and that the internet is working properly.
If the problem persists:
1. Hold down the button on the front of the printer until it flashes once. Two sheets will be printed. On the second sheet, there is a field where the IP address is shown.
2. Go to Box Office and, within the Settings section (settings wheel) > Printers, enter the Zebra printer model and the same IP that was printed before. In the field Port type in: 9100. Remember that when entering the IP, it's imortant not to write the zeros on the left.
If, after following these steps, the red cross continues to appear, it's possible that the IP which yoiu have assigned is not correct. In this case, you'll need to contact the IT department for them to check it or reconnect the printer. You can follow the instructions from the article: How to connect the Zebra GX430T printer.