Issues: The type or namespace name does not exist in the namespace in orchestration.
Reason: When we have start building solution and add orchestration. And after some time we change the name or design of the solution. And then if we create a new orchestration, that orchestration would have different namespace from older solution because solution name has been changed. So if we have two or more orchestration then they have different namespace. That’s why this issue occur when we try to build the solution.
Solution: You need to verify the type namespace in each orchestration, namespace should be unique through out all orchestration in one solution.
in short, Orchestration namespace should be same for all orchestrations under one bizTalk solution