Auth_jommdle pligin installation

Hi! I follow instruction in Wiki, but when I install auth_joomdle plugin, my Menage authentication screen is empty

I use Joomla 3.4.1; Moodle 2.6 and last version Joomdle from your site.
Where I make mistake?
Thank's in advance

Usually that behaviour is caused by some error.

Try removing the Joomdle folder, and going to Manage auth again, to see if it works fine.
If so, put joomdle back and check your server logs looking for some clue.