Sites that use MNet authentication from moodle.org now fail with the message:

Ooops! Your MNET communication has failed! Here's that error message to pass on to your administrator: malformedERROR 3:
3: malformed

OR:

Ooops! Your MNET communication has failed! Here's that error message to pass on to your administrator: User with ID 0 attempted to call unauthorised method auth/mnet/auth.php/user_authorise on hostERROR 7:
7:User with ID 0 attempted to call unauthorised method auth/mnet/auth.php/user_authorise on host

Known sites that Mnet with moodle.org:
http://coolcourses.moodle.org
http://hub.moodle.org
http://www.moodlemoot.it
http://dev.moodle.org
http://ept3.sgu.ac.jp