I have reported this to Content Server support email but also reporting here to help with visibility.
In the past hour (12:21pm onwards GMT) we have been getting numerous complaints from customers about licence acquisition failing. We also see the same problem on our PC's. The license signing server is https://eusigningservice.adobe.com. Visiting this server we get a message that the service is unavailable. Please could you advise if there is a problem?
Server status current shows UP. I'll check the logs when I get in.
I was told the signing server was temporarily out, and a reboot of our ACS4 server has restored service. Must be some issues with caching somewhere.