“initialising…” isn’t an error message
If you try to run an experiment online and you get a blank screen with the word initialising… in the centre, you need to investigate further before asking for help.
This indicates a launch error, which is usually a syntax error in your JavaScript file that wasn’t caught by the checks during synchronisation, and may be in a Before Experiment code component tab. The most common cause for this error is that you are trying to import a Python library, such as random or numpy, which don’t exist in JavaScript. Use Developer Tools to look for more information and then search for that error on the forum.