I'm just walking through a simple exercise presented in the Databricks Platform Lab notebook, in which I'm executing a remote notebook from within using the %run command. The remote notebook resides in the same directory as the Platform Lab notebook, and is named 'Notebook_B'. However, when I try to run it, a 'File not found' error is thrown. I've determined that the relative path to the notebook is correct. Might I be missing some extra bit of configuration? I've attached screenshots to illustrate.

Thanks for your time and assistance!