Problems with Multidomain and sunrise

Hi there, very urgent, cause the site is already live.

I’ve installed the multidomain plugin installed and it seems to be correct defined… but it does not work…

entering the second domain does a redirect to the main site domain

Trying to change Domain-Mapping or Domains in the network->settings lead to the following error:

Please edit your wp-config.php and move the line define( ‘SUNRISE’, ‘on’ ); above the last require_once() in that file or make sure you updated sunrise.php.

But the parameter is correctly set and the sunrise.php is there and seems to be correct…

Any help, it’s really important…

Kindest regards