Not sure when this began but the CircuitStudio Start page is showing "404 Not Found". I'm using v1.5.1 (Build 13). My subscription expired October last year. It's only a minor irritation but I would like to know if there is a fix.
It does that for me also. I noticed it yesterday but it might have been a problem before that and I didn't notice. I have an active subscription and running the latest so it does not appear to be from your version. I'm guessing the START page is trying to go somewhere that is no longer there?
Reinstalling CS did not help either. I had to do that to correct a layer stack manager issue.