I am getting HTTP-400 error and am unable to do cloud sync

Thank you for taking the time to visit the Community to post your issue, although I apologize that you haven't received a response. 

If you have not done so already, I would start by resetting the Quicken cloud. 

1. Go to Edit > Preferences > Mobile & Web 

2. Click Reset your cloud data. 

Please let me know if this resolves the error. 
 
-Quicken Tyka