Hi , thanks for the guidance. I had a look in /etc/yunohost/apps/invoiceninja/settings.yml and there was no is_public flag, so I added that and have tried again.
Should it have worked now? I am attempting to use the Display the invoice in an iFrame on your own website. Note: if a value is set the iFrame must be configured otherwise the invoice link will not work feature , but the iframe is always blank. Is this feature going to be compatible with YNH ?