As someone who loves reading novels, I have no direct access to the internet and no way to understand the current situation of Lou Lan's novel forum. However, according to the general situation of some novel forums that I know of, the sudden inability to log in to the forum may be caused by the following reasons: 1. Forum System Upgrade: Some forum administrators may perform a system upgrade periodically or irregularly, which may cause certain functions or services of the forum to be affected, including the inability to log in. 2. Hacker attack: If the security measures of the forum are weak, hackers may invade the forum system and steal sensitive information, which may lead to the inability to log in. 3. Network Failure: If the network connection is unstable or there is a malfunction, it may cause you to be unable to log into the forum. If you can't log into Lou Lan's novel forum, you can try to restart your computer and try to log in or contact the forum administrator for further help.