Error Code: 91010
Our experience has shown that this error message is typically caused by issues with your Friends Roster. Have you added someone new to your friend roster just before the problem occurred?
What to do:
1. Check your Friends Roster for any duplicate Friend Codes. Delete any duplicate Friend Codes and test the connection again.
2. Remove the newest Friend Code and test the connection.
Delete one friend code at a time, working backwards, testing the connection as you go. (Be sure to write them down before deleting them, so you can re-enter any Friend Codes that were not the problem.)