Are you trying to register user as public (not logged in user)? Then you need to give public group create permission on user form, this is set in form configuration (click small orange arrow on the right)

Yes the user can create a account CF attachement

my answer i not cear: the right is good on admin like you can see on attachement but on frontend i can't create a account :

"you are not autorized..."

So what kind of user do you use when you get this message? Check if that users group has create permissison.

Yes finaly i have chenge on global configuration and composant rights.

I can create a user on front end but by default isn't activate but on global configuration of joomla the autoactivation is ok

I can create a account on front end but by default is blocked on the admin.

But on joomla configuration i have autoactivation at yes... i have to configure something on seblod but where ?

Yes, you're right.

Thanks!