To localize any problems of the Tomcat web applications, you can examine the logging files.
Browse to the logs directory in the Tomcat application directory.
Here you can find several Tomcat log files. Choose the file which starts with “tomcat8-stdout.YYYY-MM-DD”of a specified date. The date is printed in the filename. You most likely need the most recent one so sorting by Date modified is usefull.
Open the log file in a text editor. At the bottom of this file, you will find the latest logging information of the Tomcat service. In this example the application was just shut down.
In this example there is a database connection error located in the log file.
Sometimes there where login codes reported in the Tomcat logging. These codes represent the status of the Principal Toolbox application. In the example under here, the login code 12 is reported.
In the table below there is an overview of login codes which could be found in the logging:
| Login code | Description | |
| 0 | OK | |
| 9 | Application needs database restore (rollback: update failed!) | |
| 10 | Invalid key / tool not registered yet | |
| 11 | Licence key expired | |
| 12 | Invalid machineID | |
| 13 | Too many users are activated in the Principal Toolbox | |
| 14 | Performing updates |
