Customization of navbar

I was looking to customize the navigation bar on top of the shinyproxy webpage. For that purpose, I was following the documentation provided here . Basically I used a custom navbar.html file and pointed the path for this new file using template-path option in the configuration file. I am successfully able to implement it using .jar method but when I try to use the same by editing config file (i.e at /etc/shinyproxy/application.yml) for debian based method (i.e as a service tool on debian system) its not working.

Am I missing something here?
Any help is much appreciated . Thank you…!!!