The Brave browser by design tries to limit cross-site tracking. Unfortunately, Quantopian relies on this feature for notebook security.
There is a Brave browser setting called 'shields down' which can be set for each site. This should keep the browser from checking for cross-site tracking. It sounds like you did this for quantopian.com. However, Quantopian actually uses two domains within the notebook environment quantopian.com and dynoquant.com. Make sure this is set as 'shields down' for both these domains. That may fix the problem.
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