UPDATE: The cause of the server instabilities outlined in this post have been resolved.
The MechWarrior Online servers underwent brief periods of downtime over the weekend due to an issue currently under investigation.
While services were soon restored, we are still in the process of investigating and resolving additional connectivity issues which continue to result in player disconnections. These issues will cause you to be disconnected and returned to the login screen with a connection error.
If you are disconnected from the game client and receive either 'Error 66' or a 'Server Connection Lost' error, you have unfortunately encountered the issue we are currently investigating. While the issue does result in momentary disconnection from the servers, you should be able to subsequently log back in and reconnect. Unfortunately, under certain circumstances you will be unable to rejoin a match in which you were participating.
At this time we do not require any diagnostic information or troubleshooting follow-up if you encounter the error. This issue appears to be solely related to our own servers.
We hope to have the issues resolved shortly, and will keep you updated with any pertinent progress.