Hello Philip,
some development environments check the requested URL against the FQDN in the certificate. In this case you will get an error message, if you just call the server via IP address. Just enter a domain name of your choice into the /etc/hosts (or \Windows\System32\drivers\etc\hosts on a Windows machine) of your client machine where you want to call the server.
Because you don’t need these steps if you follow my solution. The server starts automatically because of the last step (the entry in file /etc/rc.local)
Hope this helps
Uwe