The banging it on a table fix is for err. 25. nothing to do with your error26. From what I can tell, it's caused by a hard crash,and a sensor gets stuck. I don't think it is a factory advised fix, but some of the guys on this forum have used it to unstick the sensor. You'd have to read how to do it in some of the posts,they have a certain height, side,etc. you have to follow. Unfortunately, due to djis' unwillingness to help people, they have been trying their own fixes to keep flying. It's a crazy fix I know but dji won't respond to questions about fixing the problem.