LOAD_FAILED
What happened
Loading a file runs the top level of it once. When that raises an error, the file cannot be used. The message is the error's own name and text.
What to do
Fix the error the message names. Keep what runs at the top level of the file short and free of anything that can fail.
Example
text
strategy.py, line 9: NameError: name 'slow_period' is not defined [LOAD_FAILED]The wording of the message depends on your file, and the code does not. An error stops the file from loading.