If you get the 404 error, this means Headwind MDM web application wasn't deployed due to an error.
To check what happened, look at the Tomcat log. It is located at the path /var/lib/tomcat8/logs/catalina.out
Note: there was a bug in Headwind MDM control panel version 3.07 and below. It was compatible with Java 8 only, and it didn't work on Java 11. Also, the installer reported successful installation even if there was a deployment error.
The installation issues were fixed in version 3.08, please download the latest version here.
If you keep getting 404 error, please contact the Headwind MDM technical support.