What type of hardware are you using: Old laptop or computer
What YunoHost version are you running: 12.0.11
How are you able to access your server: The webadmin
Are you in a special context or did you perform specific tweaking on your YunoHost instance ?: no
Describe your issue
uPnP would not be set and reported error of port 1900 already closed/open. This was resolved for FritzBox router by doing the following
Network>Home Network>Network>Permit independent port sharing for this device TICK
Then on the yuno server go to Tools>Firewall>uPnP enable
It did work for my setup and yuno server opens and closes ports via uPnP as needed
Share relevant logs or error messages
No error message about port 1900 anymore