And I think this is the reason why:
- you should search for help there, as they maybe have their own installation way
- you are not able to install it, as InvoicePlane does have a very good and detailed manual/wiki where it is written how to install it and what the requirements are → WIKI
Yes, seems like hes trying to access it localy. But I honestly do not know if he maybe wanna run it on a local webserver 