My understanding is that if you have print plate confirmation checked, the print will not start till you set the plate as cleared on the printer page. Also, on the printer card, check if you have plate check enabled. It uses an image detection algo to check if there is something still on the build plate. I've found it to have too many false positives, so I just disabled it and am relying on plate clear confirmation. Check the screenshot to see the plate check toggle I am referring to.
