In order to set the Build order for your Solution, right-click on the Solution in Solution Explorer and Select Project Build Order:
Your Project Dependencies should be set correctly which is used to determine the Build order by Visual Studio.
The image below shows the Project references added in the Business layer to determine that the DTO and Persistence Projects should be built first before the Business layer Project.
The Project Build order will make sure the required dlls are available for the Api to compile correctly.
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