5a6 isn’t an error at all actually and it doesn’t even stand for “5a6”, it is actually designed to look like “Sab” which stands for “Sabbath”. During the time changes, many people try to set their clocks using the clock button and holding it down. If you hold the clock button down for too long, it will put the oven into “Sabbath” mode. On some models you can press and hold the Clock button for 5-10 seconds and the unit will exit Sabbath mode. On other models, you can not exit Sabbath mode until it exits on it’s own which is 72 hours later.