An important downtime of our authentication servers have impacted many services over the week-end, and prevented logging in to Uplay PC. This issue has now been fully resolved.
While players with existing accounts could switch to offline mode for supported games, it was not possible to create new accounts or register newly acquired games. We understand that the error message on the login screen - mentioning a wrong login or password - could be misleading for existing users and we would like to apologize to anyone who had troubles accessing his games during this downtime.
We are of course investigating the exact cause of this issue on the technical side, as well as reviewing ways to provide clearer information to our players in such unfortunate events.
Thank you for your understanding.