I would start by ensuring that you redirect from your application to continue endpoint directly with HTTPS instead of HTTP. Now, if this works for DB connection this would not be the real root cause although you should still do it.
Given the trace only contains the last leg of the process I would confirm that you’re NOT using Google connection with developer keys (Test Social Connections with Auth0 Developer Keys). These can be used for very simple login tests through the dashboard just to understand the feel of how Auth0 would work with social connections, but my recommendation would be to avoid them as soon as you start doing anything else.
If you are not using developer keys the plot thickens in which case an HTTP trace with the full process could be helpful, but for that one you would need to redact a lot of stuff as it could contain sensitive data.