Our LCCS account password have been resetted between August 5th (last time of successful connection) and September 21st (the day we had the connection fail).
Since then, we have resetted our password using the "Forgot Password" link on the LCCS developer portal (https://portal.collaboration.adobelivecycle.com/) and everything is working fine again. However, we were wondering what was the cause of this password reset. This is our production account so it's very important for us to know the origin of the problem.
I can provide account information if you want to check your logs, but would prefer to do so not on a public forum.