Sync Issues with Pavlovia – Stuck on Initializing Screen or 403 Error

Here are some possible solutions. Have you removed html from Experiment Settings / Online / Output path?

https://discourse.psychopy.org/search?q=AttributeError%3A%20%27NoneType%27%20object%20has%20no%20attribute%20%27project%27%20status%3Asolved%20order%3Alatest