If you see a gray screen when invoicing, please scroll down to see the entire display. The pdf viewer allows for three pages, so if the invoice is shorter, it will not fill the entire viewer. When sending or saving the pdf, it will display as usual without any gray borders.
If the screen is entirely gray and there is no invoice display after scrolling down, then this will be an invoice number issue. First check to see if you can preview the invoice, scrolling down as above. If you can preview and scroll down, but the generate invoice screen is entirely gray, please contact your manager to update the branch invoice number sequence.