This question appears to be a duplicate of How do I login to Sim Commander or the new website? | SimXperience® Full Motion Racing Simulator Technologies
We're in the process of upgrading our servers to help facilitate future innovation.
Over a month ago, we released a preemptive update to Sim Commander to ensure a seamless transition to our new servers. Unfortunately not everyone accepted the update before we made the move.
I think you probably just don't have the latest version of Sim Commander. The latest version will always be linked at the bottom of this page: Sim Commander 4 Software | SimXperience® Full Motion Racing Simulator Technologies
You will need to install this version, then thereafter, you will be able to get updates from within the software again.
I apologize for the inconvenience! We've never had a mechanism to force updates on users but are giving it serious consideration for Sim Commander 5, having learned how many of our customers are behind on updates during this process.