I just had the default settings for “Email Settings”. I realized I didn’t have the from e-mail address set. Even though I didn’t think that would make a difference, I set it and registered a new paid user. Still no dice. The user is created with the correct membership level in the eMember table, but there’s no e-mail set for it, and there’s no matching WP user created.
I’m not sure if it helps, but the subscription_handle_debug.log says: “SUCCESS:Member signup completion email successfully sent”.