I installed the e-Newsletter plugin via the dashboard on a Multisite install , and after activating it I cannot access any page in the admin area or even the site itself. All pages go to 404
My Pretty Permalink is set to /%postname%/.
There are only 2 other non wpmudev plugins on this site (assuming that the wpmudev plugins should not cause this behaviour), and these are:
1- Wordpress social invites: http://wordpress.org/plugins/wp-social-invitations/
2- UserPro: http://codecanyon.net/item/userpro-user-profiles-with-social-login/5958681
Your help is appreciated.
Thanks and regards,