This collection already contains an address with scheme http. There can be at most one address per scheme in this collection – WCF/BizTalk Error

You’ll get this error when using WCF/IIS and host headers…..fortunately a fellow
colleague Paul
Glavich figured it out!!! Well done Paul! (It involves an IIS reshuffle, you may
be able to do something within a custom WCF Binding.)

Remember: There is a limit on the number of IIS Websites you can have on a
single machine.