I’ve replace the code by the following lines, and it works fine now ??
if( ! wp_login($oid_user_data['user_login'], $oid_user_data['user_pass'], true ) ) {
$this->error = 'User was created fine, but wp_login() for the new user failed. '
. 'This is probably a bug.';
$this->action= 'error';
//$this->core->log->error( $this->error );
break;
}