No password is sent to new user

Thanks for the great plugin. But there seems to be an error: When I try to registrate a new user, I receive the notification email that a new user has registered but the email with the password does not get sent to the specified email address. If I deactivate the plugin and registrate through the normal WP regitsration form, the email is sent however.

Apache log is silent.
Sending E-Mail is setup and working.

Thanks for checking!

https://www.ads-software.com/plugins/baw-invitation-codes/