You can only create a listing with a non-admin account. There should be a more clear error message for this.
This initial journey would be great to solve, because otherwise it adds annoying friction in the initial phase.
E.g. if you really need to force that admin can't have listings, then you could automatically create user account for the admin.
I'm saying this because a lot of people that will want to create a market are doing that because they actually want to sell something and practically speaking that's the only way to really bootstrap the economy around the market.
Useful metric here would be the time from installation to the first listing...
Thanks for the feedback. We'll try to put out a new release that makes it more clear the difference between admin and non-admin roles.