I figured out what the issue is. My instances of Asterisk are running in Docker containers. The log files are being written to /var/log/asterisk in the Docker container system, not the standard Linux file system.
To access the log files, I need to enter the “docker exec” command, like this: docker exec asterisk cat /var/log/asterisk/messages
I am telling the docker system that I want to execute the “cat” command on the “messages” file in the “asterisk” docker container.