Before diving into troubleshooting the problem, it’s a good idea to read over: https://tomcat.apache.org/tomcat-9.0-doc/setup.html which guides you through the Tomcat configuration process. It might also have the exact answer you are searching for.

As root, you can try to gather more information by running journalctl -xe or find the apache-tomcat logs directory in /var/log/. The first option, if journalctl is installed on your system will give you a closer look at what actually failed. It may tell you that your configuration in the tomcat config file references a filename that does not exist, or that the apache user does not have permission to execute or read one of its directories – especially if any of those files were written by the root user. You can run chown root:apache /<path>/<to>/<filename> && chmod r+x /<path>/<to>/<filename> to any files that the apache user cannot run.