You configure a self-hosted service at a BizTalk receive location using a localhost address, and when you try to enable the service (receive location) you get the above error with the details 'HTTP could not register URL http://+:80/Sales.CreateFlightBooking.HoldFlightSegments.v1/. Your process does not have access rights to this namespace'
To overcome this issue, you need to
1. Open the Visual studio command prompt (using the run as administrator option)
2. Type in the command netsh http add urlacl url=http://+:80/<the rest of the address that comes after localhost/> user=DOMAIN\username (So, if your full address is http://localhost/company.bookings.carbookingservice, you type in http://+:80/company.bookings.carbookingservice)
3. Enter to run the command
You should then get a 'URL reservation successfully added' message
Go back to enable the receive location. It should start successfully now (I sometimes reset IIS before this step )