Confluence plugin development problem

I am trying to write my first plugin for confluence using the instructions given at Create a HelloWorld plugin project.
Instead of atlas-create-jira-plugin, I used atlas-create-confluence-plugin and it created it. Then when I used the command atlas-run, it ran and gave me the message:
confluence started successfully in 195s at http://localhost:1990/confluence
But when I try to access it in the browser, I get the following error:

HTTP Status 404 – Not Found

Type Status Report

Message Not found

Description The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.

Apache Tomcat/9.0.11

What am I doing wrong?