AD Account not working

For a few days now I cannot login to AD Accounts anymore. I receive the message "Your are unable to log in to the user account "XYZ" at this time. Logging into the account failed because an error occurred" I've logged in with a local administrator to check the AD Connection and this seems to work. After this I've checked the directory services. If I go to the directory editor and search for the user in the nodename. I can find it with all attributes. Unfortunately we are running macOS High Sierra 10.13. Time/Date is also checked. All neccessary certificates are installed.