A new person signs up and your app shows "Error sending confirmation email" instead of letting them in. Public reports show it as a 500 with the code unexpected_failure : {"code":"unexpected_failure","message":"Error sending confirmation email"} ( Supabase discussion #29703 ; also #36181 ). Password reset can fail the same way with "Error sending recovery email".

The 500 alone does not say why. The reason is written in one place, and most people never open it.

What the error means

With Confirm email on, Supabase Auth has to hand a message to an email server before the sign-up can finish. This error means that hand-over failed. Supabase's error reference says a 500 indicates the Auth service is degraded and "most often it points to issues in your database setup", and unexpected_failure means "Auth service is degraded or a bug is present, without a specific reason."

The reason is in your project's Auth logs.…