"Error loading dependencies" when using multiple processes to run

The app runs perfectly well, as expected, using single process.

When I run multiple processes, it says:

Error loading dependencies

My app uses basic authentication. Also, it does read and write values from CSV files for its functioning as opposed to some database. Do you think that might be a problem?

What are the cases where such a problem might originate. Thank you!

EDIT: There is no such a problem when I use multiple threads.

Any solutions here please?