I am developing a module in Julia. I always activate the environment in the project folder when working on the module. However, when I want to use my module by using MyModulesome functions in the module are not accessible, producing UndefVarError when being called. I have to activate the environment first, then do using MyModule in order to make it work.
You may have one version of the package installed in the main environment, which is not the same as the one you have in the project. (Is it a package?)