Localhost Multisite Configuration

Could you please provide some sample values you have set as administration domain and presentation URL for each site? To start with, I would make sure the domain aliases are not set at all - nothing for admin or live site aliases to avoid confusion.

Or, try using 127.0.0.* instead of localhost.

The site is headless, so the front end URL is handled outside Kentico.

I set up localhost:8005, localhost:8006, localhost:8007 as bindings in an IIS website and also in the Administration Domain of Sites in Kentico. Editing "Sites" works on any of them, but selecting a multisite in the dropdown gives me an "Invalid Website" error and "(current site)" in the dropdown.

If I change one to use localhost, then that one only works.

With your suggestion about using 127.0.0.* do you mean I should use 127.0.0.1, 127.0.0.2 and 127.0.0.3 as bindings on an IIS site and also as Administration Domain?

What do you mean by headless? There has to be a Kentico 13 admin app and some front end app. And in the Kentico admin you configure the site's administration domain and presentation URL - so, what are the values set for site 1, site 2, etc.?

For example I have this:
- Site 1
.......Presentation URL: domain1.com
.......Administration domain: localhost

-Site 2
.......Presentation URL: domain2.com
.......Administration domain: localhost:8080

There are no domain aliases set and domain1.com and domain2.com are pointing to separate IIS sites, each pointing to a separate front end app project. The admin app is running in a third, separate IIS site.

I think this might be a bit non-standard for an older version of Kentico. The Kentico has an API (written before my time) and the presentation URLs on stage/prod point to the front end, which is a separate NextJS application.

For my local, these are localhost:8000, localhost:8001, and localhost:8002. But I didn't think they mattered much with trying to get the back end only working.

the localhost values you have set - are these administration domains or Presentation URLs?

Presentation URLs

http://localhost:8000 http://localhost:8001 http://localhost:8002

Administration domains: localhost:8005 localhost:8006 localhost:8007

I just get "Invalid website" for all of them in the admin. If I change any one of the Administration domains to just "localhost" I can access the site in the admin.

And what is your IIS configuration for the admin app? Are all the ports set for given website as bindings?

Yes a single IIS website with bindings for localhost ports 8005, 8006, 8007.

I have this setup and it works fine: Screen shot link