Installation problem - invalid caracter - hostname

Hi,

I have a problem filling out the hostname on screen two when setting up Photos II and it does not allow med to go further on.

It seems like it should be filled out from before, however it is empty. When trying to fill out and set the hostname the error message is invalid caracters.

I found some other posts on the subject from 2014 but that gave me no answer.

Tried and failed:

Reinstalling Photos 3 times

Using Chrome, Safari and even from iPad (since one post reported browser as a problem)

Changing the name of the server

I'm not very Linux savy, but I get around and can do some changes if needed. Any advise would be most helpful.