Hello,
I want to register used domain on second project which should have subpath example.com/v2 and first site should have subpath example.com/v1. When I try to add a custom domain to a page I get the error “Another site is already using this domain”, but in the article https://answers.netlify.com/t/support-guide-can-i-deploy-multiple-repositories-in-a-single-site /179 I learned that it is possible.
2 sites
1 domain
Can you help me please?
@Luigi Based on the error you’ve mentioned it sounds like you’re trying to literally add the domain as the Custom Domain for two separate site instances in Netlify.
That isn’t possible, nor is it what the article you’ve linked to says can be done.
The main instruction in the article is this one:
The idea is that you set up a site instance which does have the custom domain against it, along with other separate site instances, and then against the main site you configure proxies that point to the other sites and mimic subfolders.
So that when a user visits content at /v2 for example, they end up seeing whatever you have hosted on https://yourotherrepository.netlify.app/.
Does that make sense?
Thanks for providing that context @nathanmartin 
! @Luigi just echoing what nathan said…you can use a proxy redirect for multiple sites to deploy off of that one domain. It sounds kind of confusing but please don’t hesitate to reach out if you need more help!