Search the “tutor local logs --tail=100” output to see if you have any particular SMTP errors on registration vs. test emails. I know I had these kind or problems when first getting set up, but I don’t remember what I found or how I solved them, only that I had to dig around in the logs.
The logs show it is (TypeError: Object of type LazyStaticAbsoluteUrl is not JSON serializable), and I found this link https://discuss.overhang.io/t/no-activation-email-errors-logged-on-user-sign-up/1969/7 about the same issue. Is there any quick fix or should I upgrade and now that we have few versions afterwards is it safe to upgrade to [v13.0.3] or should I stick to [v12.1.3] so that I don’t loose my courses and theme customization.
DO NOT upgrade to v13 if you are not ready to upgrade to Maple just yet. Just upgrade to v12.1.3.
EDIT: can I just say that I appreciated your thorough bug description as well as the fact that you searched the forum topics by yourself for a solution? This is the kind of stuff that makes my life much easier, so thank you