Please note that you need to use your LRZ ID (LRZ-Kennung) to log on to Confluence and not your LMU ID (LMU-Benutzerkennung); in case you are not familiar with your LRZ ID, you can look it up in your LMU account (https://www.portal.uni-muenchen.de/benutzerkonto/) where you can also activate it for Confluence.