Error:
A client C# program was call an orchestration published as a web service. I was turning on Basic Authenticiation in BizTalk and IIS. C# client program kept getting: “The requested service [service name] could not be activated. See the server’s dianostic trace logs for more information.

My Solution:
NOTE: This may not be your solution. We had DNS pointing a subdomain.domain.com to one of two servers. I simply had the servers crossed. I think they were having a load balancing issue, and had DNS just pointing to one of the two. Other users were on Machine A, so I logged on to Machine B, thinking that’s where the DNS was pointing. Later I confirmed that DNS was in fact pointing to Machine A.