While I am unable to find the document that I had used to setup and configure Invoice Ninja that caused my confusion, I can say that even reading the release notes / installation guide that you provide, does leave this open for the incorrect assumptions of what this field is for. According to the Installation Guide:
16.1 Settings
The Settings box has three sections – Link, Navigation and Custom CSS. Click on the tab to open the section you
need.
16.1.1 Link
• Domain: Select your preferred domain name for the client portal and invoice emails.
• Customize: Customize the portal URL with a subdomain name or display the invoice on your own website. To
add a subdomain, check Subdomain and enter the name in the field. To add your own website, check Website
and enter the URL of your website in the field.
For someone familiar with IFrames, or just this kind of development, this may be self explanatory, however, for me, and I know others that have made this same mistake, this guide does not make it clear (without looking at further resources) that this setting is for configuring another website (not the Self Hosted /Invoice Ninja site) with this setting configured so that your other website can load the clients Invoice into your other website.
Now if I was using the Invoice Ninja Cloud / Hosted plan, this may have made more sense, however, since I was setting up my own Self Hosted installation of Invoice Ninja on my own VPS server, where the guide states “To add your own website, check Website and enter the URL of your website in the field.” I misunderstood this to mean my Self Hosted Invoice Ninja Website URL.
Since I don’t know anything about IFrames, I was under the impression that this was a configuration needed get the Invoices to load on my installation thinking that on a Self Hosted installation, we could have different paths / sub-domains / URLS based on our Servers, and there for this was a required congratulation if we wanted the invoices to display properly for our unique Invoice Ninja Installation of our own Web Servers, especially if we were using a URL or Aliases that different from that of the default which for me, I was not using the Web Server installation directory of /var/www/html/nvoiceninja instead, I am not using a directory at all, even though the installation instructions recommend using the default, but I wanted to use the base directory so there would be no domain/sub-directory.
I hope you are able to see now how this could be misinterpreted and that you can make a note in the settings or at the very least the installation guide that this setting is NOT for basic invoice Ninja Setup for either Cloud or Self Hosted installations. As well, a note as the last person commented, making it clear that by setting this value in the Settings you will break the ability for anyone to login to you Client Portal if you point this setting to the URL of your Invoice Ninja Installation Client Portal. This is only to be set if you have setup a custom website separate from the Invoice Ninja Server Installation where you intent to have that custom site to display your clients Invoices.
While I realize no one wants to see the installation guide nor the Invoice Ninja Settings be updated with what I typed above verbatim, I wanted to make it clear how and why there have been a number of people who have made the assumption that this was a required field in order to allow access to the Client Portal mostly if you are running Invoice Ninja on your own Self Hosted Server. It’s very easy to misinterpret what the guide refers to saying
display the invoice on your own website" to me, the Self Hosted Installation of Invoice Ninja was what you meant when you stated “your own website”. I didn’t realize that actually means another separate website completely different from Invoice Ninja.
Cheers, and sorry for the lengthy reply.