This type of error can occur if you try to launch the game when a maintenance or patch is underway (usually on Tuesdays). The error may also indicate a problem with our servers.
Please wait an hour and keep an eye on the forums. If the problem is affecting everybody, we will probably make an announcement soon.
If the problem persists despite waiting, please reinstall the game without uninstalling it first. That way, you will only reinstall missing or corrupted files.
If this does not resolve the issue, please contact our team by sending a ticket and selecting the “technical assistance” form.