I just realized, that my Response to your answer has not appeared in this Topic. I'm sorry. Especially as you have answered so amazingly quick. I answered to the notification on my phone.
Thank you very much for this helpful advice. I have followed all the steps and at the end I started a print. It was exactly were it used to be before the Problems occured. So I'm happy that I can continue my work.
From all the possible causes that you mentioned, I guess it was the Position of the rods and the activation of the limit switch that were wrong. It was indeed no Software issue.